Not that i know of.
I know for a fact some of my papers were A's when i received a low B or C.
Especially my 20 page paper on the history of judicial activism by the US Supreme Court. It ruled.
Had a similar situation happen to me with two different "professors." I challenged both successfully by bumping my papers up to the department Deans & letting them know in clear language that I considered it liberal bias & discriminatory practice. This liberals are nothing if not hyper-sensitive to ANY claim of discrimination. BTW - once I got the Deans involved, I had no further problems with those two socialist pukes.