I was absolutely ecstatic when the recent update came with a preferred phone in my model 3. Prior to this, the car consistently connected to my wife's iPhone (I have a pixel 3), even when my phone was with me getting in the car and her was in the house. HOWEVER, the update did not fix the issue, in fact, I think it made it worse. Even with my phone selected as preferred, it still chooses the iPhone. I've even deleted it and re-added it with no luck.
And tonight, even though I'm inside and the car is charging in the garage, the bluetooth on my phone is still "on" and connected to the car. That's never happened before. Usually the bluetooth turns off if I'm out of the car.