I'm not sophisticated enough using SWUs, but is seems like the space was released and then immediately applied to someone above on the list.
My suspicion is that AA's IT technically has to "release" the seat, then it gets immediately taken by someone on the list.

Next time your alert triggers, and you are not the one who is automatically upgraded from being on the list, I would check to see if EF shows A1. If its showing A0, it may just be an automated and immediate release and application to someone above you.

Again, just my hypothesis. I'm sure someone can confirm/correct me.