Up until two days ago, I hadn't experienced a single issue with my iPhone X opening the car during the 5+ weeks that I have owned the car. The car would always respond and unlock immediately when I engaged the outside door handle. Zero issues.
However, starting 2 days ago, I now end up waiting after engaging the driver's car handle for the car to respond and unlock the door. The interior screen will light up indicating that I need to use the key card, so the car appears to be awake, but yet will not unlock. Sometimes I can walk around to another door (like the passenger door) and it will respond immediately despite that the driver's door entry attempt failed moments early. Once I successfully enter through another door, the failed door will open without hesitation. Although I even experienced a case where my first attempt to enter the car was opening the truck, which worked flawlessly (no hesitation). But immediately after closing the truck, I was unable to open the driver's door. Why did it grant me entry to the truck, yet not grant me entry to the car seconds later? The issue isn't limited to the driver'd door for me either. I almost feel like at least one of the doors is selected at random to not work on entry attempt. I may have just gotten lucky the first 5 weeks that the "selected" door was never the driver's door. Shrug.
So far it always successfully locks on me when I walk away from the car. Hopefully that continues to work without issue. *crosses fingers*.
I wasn't tempted to get a fob before... but if this keeps up, I just may. I still need to experiment with reboots on both my phone and car to see if anything changes.