There is a fairly recent updated version of the Tesla iPhone app. Might want to try it?MYP here and since 2021.4.12 I have experienced 7-10 approx instances where the car won't unlock from phone and I need to pull out the key card to get in, or if I open the car with the App use the key card to start it - very annoying. For context in 9 months prior ownership this has happened only once and I think I had the App closed at the time (iOS on iPhone 12 Pro).
I have tried re-boot as well as closing App etc and it is still occurring.
Hoping this gets cleared on next update and am also assuming for now this is a software glitch.
My wife is using an iPhone 12 Pro, and as long as she keeps the Tesla app running in the background, with "background refresh" on and "allow location access" set to always, no problems. And, of course, Bluetooth on.