This will make you laugh (and may berelevantto your situation). I had a wireless doorbell on my apartment. A button outside was radio linked to a buzzer box inside. beauty of this was I could move the buzzer around with me and would always hear it when it went off. One day the buzzer went off in the middle of the afternoon, I opened the front door only to see a man walking away from his car and going into another house. Noone was outside myapartment. Few hours later, the buzzer went off again, I opened the door and saw the same man again, walking to his car... and he drove off.... again , noone at my apartment.
What was happening, the man I saw both times, the central locking frequency his car used, was the same frequency as my door buzzer.. lol.. each time he locked and unlocked his car, I would hear BUZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ....
I have since changed to a wired doorbell, but my point here is that the key fob for some bmax's includes window operation I believe, could something like above be happening and triggering the windows to come down?