Anyone else has this happen?

I had 2 RUCs expiring so I applied one to my flight today from JFK to AUS. I go to check in this morning on the app, and it won’t let me.

(BTW I bought a main cabin ticket originally and “upgraded” to a C+ seat month ago when I bought the ticket as a PM)

I call customer service, they say it’s because the upgrade has cleared and another department needs to take the certificate. Agent puts me on hold and comes back in a couple minutes.

Says the upgrade has cleared, but she can’t assign a seat, and they’ll do that at the airport.

At SkyClub, agent says, yeah, F is totally full; I can’t give you a seat. Ask at the gate. Meanwhile, my C+ seat seems to be gone and the flight is oversold.

At the gate, thankfully, agent was able to give me back the C+ seat, but no upgrade, and the cert is showing as used in my wallet.

Has this happened to anyone else?