On the ORD-MCI leg of UA 510 (which goes BOS-ORD-MCI) the seat display shows blue E+ seats available, but I can't select one, and the tabbed classes only shows F and E-. It's been like that since yesterday. There's only two non-middle E+ seats left. Le horreur!
It was booked before the transition via the hated Carlson Wagonlit, and I used my OP number instead of UA even though these are/were PMUA flights. Weird.