update to test changes

Author: kai-ion

src/aws-cpp-sdk-core/source/auth/signer/AWSAuthV4Signer.cpp

@@ -229,9 +229,15 @@ bool AWSAuthV4Signer::SignRequestWithCreds(Aws::Http::HttpRequest& request, cons
         request.DeleteHeader(checksumHeaderValue.c_str());
         request.SetHeaderValue(Http::AWS_TRAILER_HEADER, checksumHeaderValue);
         request.SetTransferEncoding(CHUNKED_VALUE);
-        request.HasContentEncoding()
-                ? request.SetContentEncoding(Aws::String{Http::AWS_CHUNKED_VALUE} + "," + request.GetContentEncoding())
-                : request.SetContentEncoding(Http::AWS_CHUNKED_VALUE);
+        // Only add aws-chunked if it's not already present to avoid duplication
+        if (request.HasContentEncoding()) {
+            const auto& currentEncoding = request.GetContentEncoding();
+            if (currentEncoding.find(Http::AWS_CHUNKED_VALUE) == Aws::String::npos) {
+                request.SetContentEncoding(Aws::String{Http::AWS_CHUNKED_VALUE} + "," + currentEncoding);
+            }
+        } else {
+            request.SetContentEncoding(Http::AWS_CHUNKED_VALUE);
+        }
 
         if (request.HasHeader(Http::CONTENT_LENGTH_HEADER)) {
           request.SetHeaderValue(Http::DECODED_CONTENT_LENGTH_HEADER, request.GetHeaderValue(Http::CONTENT_LENGTH_HEADER));