Setting inferenceConfig is missing:

ConverseStreamRequest converseStreamRequest = ConverseStreamRequest.builder()
                    .modelId(converseRequest.modelId())
                    .inferenceConfig(converseRequest.inferenceConfig())
                    .messages(converseRequest.messages())
                    .system(converseRequest.system())
                    .additionalModelRequestFields(converseRequest.additionalModelRequestFields())
                    .toolConfig(converseRequest.toolConfig())
                    .build();

Comment From: tzolov

Resolved by #1931