I booked AI tickets for one way, it didn't let me add FF for 1 passenger so I went to modify passenger details after booking. To my surprise, the birthday was -1 day to what I've entered while booking. It won't let me update due to me entering UA FF. It complains that the FF is invalid.

When I booked another set of tickets, I doubled checked our birthdays when booking. When I went to modify passenger details after booking, the birthday is -1 day once again.

Do I need to call? Is this a website error?