Screen Keeps Turning On During Phone Calls

[Applesapples]

When I am making a phone call my phone will randomly unlock the screen despite me manually turning the screen off. This causes my ear to turn off the phone, mute, or other random annoying things. Is there a way to turn off automatic screen unlock when you are in a phone call? It's really irritating.

 

[amedlock1988]

i have the galaxy s3 btw. i've ran the sensors tests, and everything working. the screen just doesnt turn off :/, anyone else have this problem?