I'm booked to fly LHR->MIA at the end of May. I'm then connecting on to an AA flight (code shared BA) from MIA->MCO a couple of hours later.
I'm doing the same in reverse on the way back a month later. All 4 flights are on the same BA booking. The 2 flights between MIA and MCO are both AA operated. On the BA side, I can see my allocated seat numbers, but the first AA flight says "Seat requested not yet confirmed".

I'm able to manage my booking through the BA website, and I'm directed to the AA website for the AA flights (obviously). However, on the first of the AA flights, I get a message saying "we couldn't display trip details" and referring me to AA customer service. The second flight is fine and accessible on AA, and I can look at my seat and flight details. If I contact AA customer service, they tell me to speak to BA, since it's "a problem with the way the flights have come over from BA's systems". However, BA tells me the problem is on AA's side, so I'm going in circles.

My concern is that I won't be able to check in online when the time comes, or pick up my mobile boarding pass.

Has anyone seen this issue before, or can anyone provide any assistance as to how I can get this resolved? Of course I could wait until I get to LHR on the day of departure and get it sorted there, but I'd feel more comfortable if everything was confirmed before then.

Thanks in advance.