Liftmaster problem

[I'dluv2]

I have 2 doors I'll call A & B. A works fine now, and B works within limits. 2 remotes both work on A, neither on B. Figured maybe needed re programming but still no go. Door B works with button on wall, light comes on . If B is open & I close and break the beams it goes up and flashes like normal. If both doors are up and I walk thru the beam the light comes on for A. If I walk thru the beam on B light doesn't come on. Only thing I can think is maybe something on the board went haywire.

I replaced the board on A 2 years ago and everything is fine now. Any guesses or ideas are welcome.