After checking in for my flight tomorrow, I can't view/change my seats for tomorrow's segments from the itinerary page (although I still can for the return) unless I'm on the check-in screen. This is a new bug even since my last flights earlier this week.

As I and others have mentioned in this thread, the seatmaps linked from the check-in screen do not correctly display the available preferred seats, as if the check-in page seatmaps don't "see" that I'm eligible.