[CampWinican]

I haven't had that problem with my vent covers, although I did buy and install the MaxAir vent covers over the top of all 3 of my vent covers. I do have a problem with my plastic rain gutter spouts and the plastic joint covers on the outside edges of my sofa slide. These plastics too have become very brittle and break when you bump them. Must be the "high quality" plastics that they use when they build these things.

I would suggest you cover your vents with the MaxAir vent covers to avoid any future issues with your vents. Then you can leave your vents open even when it rains!