I'm sure this is a newbie question, but I would appreciate your help in understanding it.

I am waitlisted for the redeye tomorrow night from SEA -> IAD (36 hours). I am 2P and was under the impression that upgrades should clear in 48 hours. I'm trying to upgrade with a regional upgrade certificate. SeatCounter shows 3 F seats available, however .bomb shows me as now waitlisted.

Can anyone explain why the upgrade didn't clear even though there are seats available?

Thank you.