i read all previous posts, and it seems all my settings (DND, during activity, etc) are fine.
My automatic backlight works fine the whole day, then when my sleep time kicks in, it stops (as it is supposed to do), but then the day after it is never back, i.e. the gesture does not trigger the light as it did the previous day.
Everytime i have to go back to settings, just to check everything is fine and without changing anything. Then it works again. Some other time i simply press the light button few times and it resumes the auto backlight.
So, I was not able to understand what makes it work again. Any help?