The other day as I was entering a car wash I began rolling up the windows both were about half way down the drivers side went up no problem but for some unknown reason the passenger side went down even though I pulled up on the switch. Thankfully, after it went all the way down I released the switched and pulled up on it again and it went up before my Z4 became a bath tub. I did a few more tests after the wash and when the window on the pass side is completely up and I pull up on the switch it went down again. Is this something that is normal? Should I have BMW look at it? I figured I would ask other owners before going to the stealership.