I'm on US915 tonight 2/1 PHX-SFO. I notice on the seat map today that Row 10 (A321) is no longer showing with green dots as preferred seating. Row 22 no longer shows green either. There are still other preferred seats showing, including Row 23 and the usual random window or aisle I don't think anyone's ever understood.

Do they become airport-assigned only on day of departure? A preferred member can't select exit row if buying online the day of travel? Row 10 and 22 are open save for 10F right now. Unusual.

Separate topic - my silver upgrade cleared and put my girlfriend and I in 1D/1F on both outbound and inbound. I moved us on one of the flights to 2A/2C, and 1D/1F still remain blocked on the seat map. That's annoying if I wanted to move back.