diff --git a/modules/openapi-generator/src/main/resources/csharp-netcore/api.mustache b/modules/openapi-generator/src/main/resources/csharp-netcore/api.mustache
index ce2000f63e9..c4824e8db8a 100644
--- a/modules/openapi-generator/src/main/resources/csharp-netcore/api.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp-netcore/api.mustache
@@ -415,21 +415,21 @@ namespace {{packageName}}.{{apiPackage}}
             {{/isApiKey}}
             {{#isBasicBasic}}
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + {{packageName}}.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
             {{/isBasicBasic}}
             {{#isBasicBearer}}
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
             {{/isBasicBearer}}
             {{#isOAuth}}
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -640,14 +640,14 @@ namespace {{packageName}}.{{apiPackage}}
             {{#isBasic}}
             {{#isBasicBasic}}
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + {{packageName}}.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
             {{/isBasicBasic}}
             {{#isBasicBearer}}
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -655,7 +655,7 @@ namespace {{packageName}}.{{apiPackage}}
             {{/isBasic}}
             {{#isOAuth}}
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs
index 57a99469634..5f1dae74c24 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -2188,7 +2188,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2336,7 +2336,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2634,7 +2634,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2724,7 +2724,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/PetApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/PetApi.cs
index 39d2e425e63..b42f2c168ba 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/PetApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/PetApi.cs
@@ -633,7 +633,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -723,7 +723,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -793,7 +793,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -865,7 +865,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -954,7 +954,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1045,7 +1045,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1136,7 +1136,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1229,7 +1229,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1451,7 +1451,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1541,7 +1541,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1618,7 +1618,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1697,7 +1697,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1776,7 +1776,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1857,7 +1857,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1939,7 +1939,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2023,7 +2023,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs
index 57a99469634..5f1dae74c24 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -2188,7 +2188,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2336,7 +2336,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2634,7 +2634,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2724,7 +2724,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/PetApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/PetApi.cs
index 39d2e425e63..b42f2c168ba 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/PetApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/PetApi.cs
@@ -633,7 +633,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -723,7 +723,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -793,7 +793,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -865,7 +865,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -954,7 +954,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1045,7 +1045,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1136,7 +1136,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1229,7 +1229,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1451,7 +1451,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1541,7 +1541,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1618,7 +1618,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1697,7 +1697,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1776,7 +1776,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1857,7 +1857,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1939,7 +1939,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2023,7 +2023,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs
index 57a99469634..5f1dae74c24 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -2188,7 +2188,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2336,7 +2336,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2634,7 +2634,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2724,7 +2724,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/PetApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/PetApi.cs
index 39d2e425e63..b42f2c168ba 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/PetApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/PetApi.cs
@@ -633,7 +633,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -723,7 +723,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -793,7 +793,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -865,7 +865,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -954,7 +954,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1045,7 +1045,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1136,7 +1136,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1229,7 +1229,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1451,7 +1451,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1541,7 +1541,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1618,7 +1618,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1697,7 +1697,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1776,7 +1776,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1857,7 +1857,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1939,7 +1939,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2023,7 +2023,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
index 57a99469634..5f1dae74c24 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -2188,7 +2188,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2336,7 +2336,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2634,7 +2634,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2724,7 +2724,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/PetApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/PetApi.cs
index 39d2e425e63..b42f2c168ba 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/PetApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/PetApi.cs
@@ -633,7 +633,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -723,7 +723,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -793,7 +793,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -865,7 +865,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -954,7 +954,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1045,7 +1045,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1136,7 +1136,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1229,7 +1229,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1451,7 +1451,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1541,7 +1541,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1618,7 +1618,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1697,7 +1697,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1776,7 +1776,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1857,7 +1857,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1939,7 +1939,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2023,7 +2023,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs
index 57a99469634..5f1dae74c24 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -2188,7 +2188,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2336,7 +2336,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (http_basic_test) required
             // http basic authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password))
+            if (!string.IsNullOrEmpty(this.Configuration.Username) || !string.IsNullOrEmpty(this.Configuration.Password) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Basic " + Org.OpenAPITools.Client.ClientUtils.Base64Encode(this.Configuration.Username + ":" + this.Configuration.Password));
             }
@@ -2634,7 +2634,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2724,7 +2724,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (bearer_test) required
             // bearer authentication required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/PetApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/PetApi.cs
index 39d2e425e63..b42f2c168ba 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/PetApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/PetApi.cs
@@ -633,7 +633,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -723,7 +723,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -793,7 +793,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -865,7 +865,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -954,7 +954,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1045,7 +1045,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1136,7 +1136,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1229,7 +1229,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1451,7 +1451,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1541,7 +1541,7 @@ namespace Org.OpenAPITools.Api
             }
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1618,7 +1618,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1697,7 +1697,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1776,7 +1776,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1857,7 +1857,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1939,7 +1939,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -2023,7 +2023,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCoreAndNet47/src/Org.OpenAPITools/Api/PetApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCoreAndNet47/src/Org.OpenAPITools/Api/PetApi.cs
index 08b2900cec6..3912ab8d5f7 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCoreAndNet47/src/Org.OpenAPITools/Api/PetApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCoreAndNet47/src/Org.OpenAPITools/Api/PetApi.cs
@@ -571,7 +571,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -648,7 +648,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -718,7 +718,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -790,7 +790,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -863,7 +863,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -938,7 +938,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1013,7 +1013,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1090,7 +1090,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1299,7 +1299,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1376,7 +1376,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1453,7 +1453,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1532,7 +1532,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1611,7 +1611,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }
@@ -1692,7 +1692,7 @@ namespace Org.OpenAPITools.Api
 
             // authentication (petstore_auth) required
             // oauth required
-            if (!string.IsNullOrEmpty(this.Configuration.AccessToken))
+            if (!string.IsNullOrEmpty(this.Configuration.AccessToken) && !localVarRequestOptions.HeaderParameters.ContainsKey("Authorization"))
             {
                 localVarRequestOptions.HeaderParameters.Add("Authorization", "Bearer " + this.Configuration.AccessToken);
             }