this happened to me before, I was 2 of 3 on the Upgrade list. with 1 seat.

I didn't get it told to board, while I was sitting in 18E a Delta Employee sat next to me, I knew he was delta because he had a leather delta binder etc and he was talking to the FA about delta policy.

When all of a sudden the GA comes and says one of the people in F missed their connection and I thought she was talking to me and was about to hand me the seat but she handed it to the delta employee. Every time I see that gate agent at JFK I give her the evil eye.