I have a C207 E250 coupe and recently the rear window does not always automatically close fully when the front window is closed. I can close it manually. Those who know the car will know that when a front window is closed on this pillarless model the back window retracts slightly while the front window closes and then returns to a closed position when the front window is fully closed. Has anyone else experienced this? Is this a fault or is there something out of synch that can be reset?