Omg, how did you find that!?

This may sound very silly, but one thing that works for me is to unlock the phone BEFORE plugging it in. But sometimes, it seems to be the other way around, where you should unlock AFTER plugging in the phone. I don't know what the root cause is, I just know doing this usually helps for my case. I'm on iOS 13.4.1, Xcode 11.7, and had this problem yesterday. Unlocking the phone BEFORE plugging it in fixed the problem.