I have a multi-leg flight starting tomorrow. For the first leg (LAX > LHR), I reserved a specific seat when I booked, but it's showing me "seat choice available" and when I tried to check it, it was asking me to pick a (different) seat. Ultimately, it wouldn't let me check in and said I had to at the airport.


This is in contrast to the second leg, where it clearly says "seats confirmed".



Any idea what's going on? Really hoping I don't have to sit in a middle seat...