The current version of openapi-generator-cli (4.3.1) uses RestSharp 105.1.0 for its C# code generation. RestSharp 105.1.0 has a known bug in its proxy-implementation. A later version (106.3) has fixed this bug. Could you please update this dependency. If I manually change the RestSharp.dll to 106.3.1 I get a compile error in the generated code.