Have a Y, but my driver side window is venting on it's on at time also.
Be sure that you aren't accidentally rolling the window down when you exit the vehicle. Unlike most vehicles, the power windows will still work when you open the door to get out (since there is no "Off" switch on our vehicles), and the switches can easily get depressed if you use the armrest to get out of the car.
By the way, had to laugh, the power windows on my 65 Buick work all the time, just like my Tesla. GM was way ahead of it's time!!
Keith