We have a 2013 Premium Van and are on our third over cab skylight. The first (original) one allowed water to creep in between the two acrylic surfaces. I could see the water moving about but it never came into the vehicle. The replacement skylight ballooned in the moderate heat of autumnal France. On return to the van I attempted to cover the skylight with the blind and was surprised to discover that it collided with a bulge that had not been there before. I removed one of the little stoppers at the corner of the skylight, and pressurised air escaped. The bulge was reduced but the window did not return to its intended profile. Both of these skylights were replaced under warranty. I have permanently removed one of the stoppers in my third skylight, although the material and design appear to have improved. I’m not sure if the same thing could happen, but I won’t take the risk.