This problem is not a screen timeout problem.
My wife has a new Droid Ultra within the last 11 days. She will wake the phone number, unlock it, and pull down her notifications all within a couple seconds and then the screen will shut off.
She then has to press the power button again to wake it up and unlock it.
It's not a screen timeout issue because it's set to two minutes and it happens within seconds of waking up the phone. sometimes she's even scrolling around on the screen when it happens.