I have 4 round marks on the glass of my rear hatch about 3" in diameter. These marks only show up when I leave the car outside overnight and there is a buildup of condensation. Most of the time I never see the marks. When I picked up my car from the dealer I only noticed 1, but I figured that I could clean it off. So far I have not been able to get them off with normal glass cleaner. I will try alcohol and acetone next. I am assuming that they are suction cup marks from the installation at the factory. The are also signs of some type of liquid running down towards the wing from these marks.

Has anyone else seen these marks?