Double tap to wake stops working.

[charlwillis]

Turn any battery saving modes off. Tap to wake is a battery drain to constantly monitor for the double-tap signal. If you have battery saver mode on, tap to wake switches off. It's a design feature.

 

[BobLad]

Double tap now works all the time on my 3XL. I discovered that tapping quickly and very lightly works. If I tap the way I usually do everywhere else, it seldom works.