Proximity sensor problem i6

The proximity sensor on my 2nd i6 is not turning off the display when it should. I noticed this when the phone would get hot next to my ear/face when on a call. I have tried repositioning it many times. Hard restarts.....left side, right side. Nothing helps.

Sometimes it works fine.....

Apple replaced the first one 3 weeks ago. This one started started doing the same thing 2 weeks ago.

I hate to call Apple back. I am sure they will say it's the way I hold it. But I've never had this issue with any iPhone going all the way back to the original iPHone 1.

I am wondering if anyone else is experiencing this problem.