I recently test drove a Model Y, when i was there I noticed the service center was very busy. I also see a lot of posts about service centers being backed up. I don't see much recommended yearly maintenance for the Model Y listed, I assume other Tesla models are the same. This being the case, why are the service centers so backed up? I know about delivery problems needing to be fixed and have seen some posts about rear motor failure. What else is going on with these vehicles that are causing the service bays to fill up?