C1 space opened up within the airport checkin window, upgrade didn't automatically process even though I as #1 on the list since we are within four hours of departure. Seat is now gone. Why didn't it clear when the C window opened up; now it looks like someone bought it an hour after it cleared because AA didn't auto process it. Kudos for selling it, but perhaps another SWU pax took it, who knows? As #1 on the list, I should have gotten it once the C1 space cleared. I have Expert Flyer so that's how I know it became available.