Sometimes when using the express up feature on the driver's side window, it will roll back down on it's own, the anti-pinch feature activates. It does this mostly while driving over speeds of 55 MPH. I think it has to do with cabin pressure building inside while rolling the window up completely. I noticed that if I leave the passenger side window down and use the express-up on the driver's side, it will roll up completely without rolling back down. It could also be a defect in the power window switch, pinched wire somewhere, bad relay... something.