Problem with Backlight/Gesture BUG?

The backlight gesture feature on my Fenix5 is working sporadically...

I have turned off the DND, set "Gesture" to "ON" on both "Watchmode" and "Activity Mode", but the backlight wouldn't turn every now and then...

At first i thought it was only in the morning (sleep hours), but i realized that even during non sleep hours, the same problem also happens...

I had emailed Garmin support but have yet to receive any replies... :(