Another thing I've noticed, surprised it took this long actually. If I use my quick gestures (except the camera one) it unlocks my 6T, surely that has to be a design flaw somewhere? Just for example, I have the 'S' gesture set to open Spotify and sure enough it does. However a quick press of Home or Back and I'm straight into my desktop. I have made sure to do it away from my face so I know it's not face unlocking.
This would also explain why the phone has been unlocking in my pocket, even with pocket mode. My 'M' and 'W' gestures also do it.