You should dig on these forums for this... it's likely a setting. The Tesla app likely needs some special permission to run in the background.
This is definitely incorrect.
For me, I believe it happens about 25% of the time, with one exception that is nearly 100%:
If I've just gotten out of the car, and closed all the doors, then it has a very impatient timer even if I'm right next to the driver's door, where it locks (beeps, mirrors fold). Then it stays locked even if I try to open the door. I think this is unrelated to the main bug, I think this is all about it being bad at determining proximity, and "solving" that problem with paranoia.
One thing I have figured out is that it is not necessary to do anything at all with the phone, and it does not necessarily have anything to do with how long you wait. Both of those things *can* get its attention, even if I don't do any of that, trying to open other doors usually nudges it into attentiveness. Sometimes I have to go back & forth between front & rear driver's side. Occasionally I have to try one on the other side. Most of the time, just one pull on the other door that's on the same side I'm already on will get its attention, and then it will unlock (mirrors will unfold), and then the door I want to use will work the next time I try it.
I also think there is something else going on besides "complications with the phone" because I bought a fob precisely due to the fact that this issue was so bad for me. The same thing happens with the fob, virtually no difference.
My best guess is that this is a hack that a BMW lover snuck into the code to embarrass Tesla for not having the "wave foot under car to unlock" feature. I'm fairly certain of this b/c it almost never happens when I have a free hand, and it almost always happens when I have an armload full of stuff and can barely free up three fingers without dropping everything. Obviously the cameras are analyzing the level of inconvenience I'll experience by it not working first try
In all seriousness, I've heard the theory about enabling background processing for the app. I've had that enabled for years (2020 MYP) and it has never made a difference.