Our Redfish service does not support HTTP method "PUT". When send a request "PUT /redfish/v1/", it will return "501 Not Implemented". When send a request "GET /redfish/v1/Invalid", it will return "404 Not Found".
Which return status code is correct if sending a request "PUT /redfish/v1/Invalid"? "501 Not Implemented" or 404 Not Found"?
At that level it really doesn't matter; you're dependent on the ordering for how your web server performs upfront checks (in this case URI checking vs method support checking). There's nothing in HTTP which dictates which one you do first, and we don't have requirements in Redfish for this ordering either.