Got this while checking in today, both for myself and MrsITAG. Flight pass bookings. Something is definitely wonky with FP ... including the previously aforementioned errors which are popping up when trying to view bookings.

Note - this error came up on two screens during the check in process. I never had to provide details for the return flight. The checkin was successful, so this just seemed to be a little bit of random Web vomit along the way.