I have a new GM 60 (almost three weeks of use), and the ceiling tiles have dropped TWICE. I'm not slamming the door or hitting them. They just have randomly dropped. The first time the service guy came out and put them back in place (took him 30 seconds) and cautioned me not to hit them (I hadn't). The second time was last night and both tiles have dropped. I haven't done anything about them yet (it was a Saturday night and no one was open) but this is frustrating to me! What is happening and why?