IIS remove header before diagnosed as invalid

The reverse proxy (IIS ARR) gets http request with invalid encoded http headers.

IIS Request Diagnostics:

MODULE_SET_RESPONSE_ERROR_STATUS
ModuleName="ApplicationRequestRouting", 
Notification="EXECUTE_REQUEST_HANDLER", 
HttpStatus="502",
HttpReason="Bad Gateway", 
HttpSubStatus="3", 
ErrorCode="The parameter is incorrect. (0x80070057)", 
ConfigExceptionInfo=""

How can I remove these headers before the request will be diagnosed as invalid?