iPhone 11 Pro Max - Proximity Sensor after lock and unlock

When I unlock phone and call somebody screen goes black normally but won't turn on so I can press end call. But if I DON'T LOCK the phone and call people again everything works great, like no delay, no problems with proximity sensor.

But.. when I lock phone, unlock again and call, same problem. Proximity Sensor does not work or delay is like 3-5 sec.

Yes, I have full screen protector but proximity sensor works great if I don't lock the phone before calling somebody.

Any advice? Software iOS 13.3.1 problem?