May be worth checking what passport is recorded at your profile level. You can check this in "Manage My Account>>"Update my personal information" and scroll down to "Advanced passenger information".

EDIT: just to add, one of the problems when you get a new passport is that even when you change the passport at profile level it won't change the API in any existing bookings - so you have to go in to each booking and change them all individually, which is a fairly tedious task!