A new one, at least to me: 4 seats open in J within 72 hours of departure, I’m number one on the upgrade list so I call to get cleared (waitlisted from W with +P).
The agent gets it done but makes a point of checking my outbound which I had flown in paid J. And goes on to say that the only reason she can force clear the return is because I did not get upgraded on the outbound already. I did not challenge it because I was getting what I wanted anyway, and because I wasn’t sure if this is a known thing that I just had somehow missed, but if not and if the agent was correct, that would be another unfortunate extension of the “Special GS benefit on one segment only” rule.