Are there 2 low power states?

I have a WF that only displays the time in low-power mode and many other things when not in low power mode.

Sometimes I do the gesture "look at the watch" (twist the arm...) and nothing happens (I can do the gesture as many times as I want, nothing happens). In fact even after I click the back or light button nothing happens, the watch is still in low power mode.

However when I "wake" it up by up/down buttons it works: it displays all the data for 10 seconds, and then it only shows the time. AND after that (at least for a while) the gesture does work.

What can cause it not to wake up? Can it be a bug in the WF? Or is it a bug (or feature?) in the watch? Maybe after the night (I have the Normal bed/wake time set) it stays in the lower-low-power mode until I wake it up with the up/down button?