Backlight does not work after timer expires

1. Settings -> System -> Display -> General Use -> Alerts -> On.

2. Start timer.

3. When the timer expires, pay attention to the screen.

 

Expected result: The backlight turns on according to the configured timeout (Settings -> System -> Display -> General Use -> Timeout).

Actual result: Backlight does not turn on.

Garmin Forerunner 955, software version 19.18