Default Nexus 5 face dialing digits on the phone?

Seems to do it more with ART, and a lot of the times when I'm on a call and hit the power button to wake the screen, the phone app will be in background and not pulled up on the dialer screen.

Anyone else? It might have done this on Dalvik too but not nearly as much.

Proximity sensor works too in my testing with my hand in front of it from the distance, and up close too..

Edit - I'm a fool. Proximity sensor doesn't work when dialer is pulled up. Will remember to get that screen out of the way after dealing with call prompts
Nexus 5 16GB Black