I called AA and got a super helpful person after about a 2-minute wait. She said there was something "odd" about the PNR but didn't elaborate. She was able to see the Y+ cabin and assign me seats without any problem. Later I asked her to remove my IB number and add my BA number but this she was unable to do (though she tried a couple of times). This is pretty much par for the course when you buy tickets from IB.