Backlight won't stay on while on watch face

I set my backlight to "No timeout" on Watch Mode (also Keys off, Alerts off, Gesture off, and Brightness 5%, if that matters) because I like to control when to turn it on or off (hate timeouts).

Used to do exactly like this on my old Fenix3 and it worked flawlessly, but on 935 the backlight stays on only when navigating through the menus. If the watch is on watch face it will timeout in just about 8 seconds!

Is this a bug and should be reported to Garmin or is it a common behaviour in new Garmin watches (maybe to preserve battery life, but again, it should give me at least a couple of minutes, not just 8s)?