Caravan windows torn down without reason ??

Hello together, since last vacation is our WW, a hobby Excellent 460LU Bj.2012, as always on closed, video-supervised terrain. Yesterday I wanted to get diving glasses and snorkel from the WW for my son and thought when I am there I can “vent” some times. So first roof hatch open, then windows at the kitchenette. First window closure opened, there was the whole window already outside on the ground. The only thing I noticed before, that between the The disc is completely torn off on the 80cm long hinge!! For me a phenomenon. There is no other damage to the caravan so I exclude vandalism, even on the disc no damage except the total damage of the case. How can something like this happen??? The caravan is fully covered (but 500€ SB ) and in the partial casket with glass break also for plastic windows, I talk to the insurance consultant tomorrow and hope he “hi There is no cause. Where would I get a new original disc? Or do others fit with the closures etc? The opening is about 72x35cm The disc is about 85x46cm LG Mickey