3 times in the past 3 months the driver side rear (passenger) window on my 2011 Traverse goes down on its own while driving. Each time I was driving over a transition (small bump) in the road at low to moderate speeds. As soon as the rear wheels hit the bump, the window goes down and I am unable to get it back up. I have had the actuator replaced twice. Anyone else have this experience or know what causes it?