This happened to me back in May or June as well on my early May delivery car. I stopped by the service center and they glued it back in place (since it just fell out when I went to charge one evening at home). I think I heard from someone that there was an issue with some of the glue used to attach it at the factory so they just used whatever adhesive was prescribed for it. Haven't had an issue since. As long as you don't lose the old one, it would seem that gluing it back in place solves the issue, whether Tesla does that or (in a pinch) you do it yourself. Seems like a pretty minor issue in any case (especially if that's the only thing that goes wrong, and I've not even heard of it happening to anyone else in my area). Still absolutely loving my car four months and almost 7000 miles in...