Originally Posted by
ethernal
It appears that this is a bug as Delta has made it clear that an upgrade will give you the boarding status of the seat.
When were you upgraded? At the gate? Did the app refresh the seat properly?
The DL app tends to have a problem updating your zone if you where upgraded after you checked in. I would guess that this is can be a common issue for FOs since UGs don’t happen until T-24 and you may check in before you are upgraded.