Good shout on ALBUMARTISTSORT mate, had the prob tonight and sorted it after reading your post.
It was exactly as you described, I had an album by the artist who was incorrectly being assigned to compilations where ALBUMARTISTSORT incorrectly had “Various Artists”.
I amended the ALBUMARTISTSORT tag to contain his name, removed his album from my lib, also removed a couple of compilations that had been mistakenly tagged against the artist, emptied the trash, re-added both his lp and the compilations back into my lib and all was good.
I’ve left all my compilations with “Various Artists” in ALBUMARTISTSORT and all seems ok so far.
Nice one 
