For as long as I can remember my phone key works flawlessly most of the time regardless of whether the Tesla app is working in the background. I’ve noticed now I have to manually open the app wait a few seconds and then it finally opens the door. I made sure to run location services at all times and I have the iPhone X. My Bluetooth is always on.It’s really annoying. I can’t remember if it’s a setting on my phone or the car that enables the app to run on the background all the time while Bluetooth is enabled.