calling Toybox.Attention.backlight(1.0) flashes the screen

widget in full view 4.1.7

A call backlight(1.0)  - screen on and it is on according to settings e.g. 8s

B call again backlight(1.0) before it off e.g. at 4s in example A, first it off and immediately on and screen flashes - system should simple extend the backlight on time