I haven't bothered asking Tesla to explain the unreliable unlocking, since it seems to happen to almost everyone else periodically, and some people quite a lot. I just take the phone out of my pocket and hold the door handle open for a while until it figures it out. After 10 or 15 seconds I usually just take out my wallet and use the RFID.

I also started using sentry mode even in my garage, which helps tremendously, because it seems like the root cause is the car going to sleep.

Usually for me it's unreliable only when line of sight from phone to car is blocked. That's with an iPhone. I hear Android devices have more issues.

Edit: And the new fob is awesome. Different tech from the old one as you've probably heard, with different security/convenience tradeoffs. (With the old one being more secure, but to an insane level, and the new one being ever so slightly less secure but still very good in my admittedly fuzzy understanding of it). No issues whatsoever since getting that.

Do you kill the Tesla app on the phone regularly? It takes a bit for it to unlock the phone in that case. Did you try changing your phone? (Not to be offensive, just curious)

Yes this is a good point too. It makes sense that there might be some delay added when the OS has to start the app in the background to respond to an event the app has registered for (...didRangeBeacons...) and maybe one of the reasons they recommend against killing the app!