I am having this issue with AA codeshare with BA flights JFK-LHR (and v.v.) but in A class which is wide open, but AA website does not pop up the couple of flights I desired, but the rest came up. Also noticed something is not right which happened before that F7 but A0 during a couple of weeks in June (again wide open) but later on (~ a week or 2 later) this was “normalized” again , or at least this time I hope it will.