Side/rear Glass problems of the 2010 Ford Mustang

I was standing outside of the car. I unlocked the vehicle. Driver side door was then opened. When driver's side door was opened, the passenger side window shattered. The car was in a parking lot and stationary. Nothing hit the window. Nothing was thrown at the window. Again the passenger side window shattered when the driver's side door was opened. The window was tinted and is what kept the glass from scattering all over the ground and in the car. The window itself is believed to be defective but cannot verify this. It is also believed that there might have been an issue with the window mechanism not being properly adjusted but also cannot verify this. The vehicle is currently at the dealership to have the window replaced. Dealer noted that this is not a warranty issue and that the warranty will not cover this. The cost of replacement is around $500. The dealer is going to look into the mechanism, track, and whether stripping to verify that this was not the cause.