Recently I realized that turning on the seat heaters from the app does not work. The app shows they are on, but when I get to the car, the seat is cold and the panel indicates the seat is not on. Same for the steering wheel. The cabin heat can be operated just fine (fortunately, since it has been cold and snowy here lately!). But at least those related features do not seem to be working, and they did used to work. I do not know when this started, and I have not had a software update for some time. The car is on 2020.48.12.1. My phone is an Android, in case that matters. I seem to recall having seen other complaints about this, on other tesla groups (Facebook, maybe) but had not verified it in my own car until recently, so this may be "old news."
But maybe I am wrong! I went to a dental appointment today, and turned on preheat, including the seat, as I was checking out at the end of the appointment. The seat was hot when i got to the car a few minutes later! So does this possibly work sometimes but not others? Does it depend upon how long the preheat lasts? Does it possibly time out (which would make sense, actually)? I will need to pay closer attention or maybe do some tests....
What I suspect is that the phone app works as expected EXCEPT when you approach your car your profile is invoked overriding what you had set from the phone. This happens to me nearly daily.