I live in Southwest Florida. I recently had a crack that developed on the rear panel of panoramic roof. The crack originated on the posterior portion of the glass, halfway in between. The crack in the rear panoramic sunroof was a result I was told of something that became lodged underneath the glass and caused pressure on the glass from the inside out. This could be from a pebble or small branch. Between the pressure from beneath the glass and the heat from outside it caused the glass to crack. Clearly this is a fault with the engineering of the product. Every other car that I have owned that had a lift gate mechanism, there was some form of felt or rubber in the gap in between. Here we have a very pronounceable 0.25 inch gap that would allow anything to get in. How is then this crack, which the installer told me that was due to something getting underneath the glass, a fault of mine and not the design of the vehicle.
Personally, I believe that this gap between the rear glass and the lift gate needs to have a rubber filler or piece of felt filler. Leaving this gap allows for anything to slip in, as the glass repair man at your service center explained, which would then allow for pressure to build up underneath and cause the crack.