I had similar experience to original poster. I am driving a 2017 Tesla Model S at 35k miles under warranty. As I was backing out of my parking spot and cranking my wheel, I head a pop and grinding noise in the front driver side wheel well. I got out for inspection, sounded like I ran over large plastic bottle and was pivoting on it, but observed nothing on the ground and couldn't see anything wrong. I got back in and proceeded forward only for the grinding to resume. I got out to observe again and found that my wheel has caught the back end of my wheel well cover and ripped it off and pulled it forward, still inside the wheel well. A firm tug removed the cover from the well. I still couldn't see the control arm, but I did observe that the wheel was set way back in the rear of the wheel well. I called Tesla Roadside and they came to pick up the vehicle.
Tesla later determined that "outside influence" was at play due to very minor scuff marks under the sides of my bumpers and some small knicks to my battery pack, saying that it would not be covered by my active warranty. The control arm had completely broken off and they wanted to say I was in an accident. I think this is outrageous as there has been a well documented history of control arms failures for this model Tesla. They've lowered the prices on their cars recently, so I guess they are going to cut costs and do anything they can to not fulfill their warranty obligations.
What are my options? I've looked to BBB, but it's very apparent there that Tesla does not care. Submit my complaint to NHTSA? Sue? I've spoken with the service manager, they don't seem to care and says it's out of their hands since I've already paid.