I have a 2017 Model S with a solid metal roof and about 28K miles on it. Over the last year, I started hearing a popping noise from the headliner when hitting even small bumps or driving over a surface that causes some flex to the car (e.g., turning into a driveway ramp). Local Tesla service has made multiple attempts to fix it, but the noise always comes back after a while. After a year of attempts, they finally tried to claim that it is "normal" and a result of a reinforcing bar striking the A pillar. Of course, it is not normal, and the noise is sometimes constant, depending on the road service. I may need to escalate this to get good results, so please let me know if you've experienced this or, better yet, found a permanent fix. Thank you very much.