I flew SJU to ATL yesterday on DL428. Today when I looked at my activity it showed my paid/flown as D/Y.

Any reason why my class paid would show D after the flight, which seems to be discounted business according to Google? I haven't seen this one before, my receipt from booking shows my fare as a Y. I was only offered seat selection in coach at purchase.

I was #1 on the upgrade list, which showed 1 available on app until 1 hour before the flight when it went to 0 and no upgrades were processed.

Ended up in the EC bulkhead row, which was fine. Ton of leg room.