1) it happened to me (I viewed the actual PALL list and saw my upgrade with a BXP waitlisted for C fall behind elites of same level requesting a Comp R waitlisted (they also had lower fare classes)
2) I asked at the AC and they pulled up some internal page on upgrade priority that vaguely seemed to suggest the same thing
3) someone else reported calling the phone center (don’t know if it was meeting services/business extra or EXP line) and they confirmed as well