SUMMARY The configuration for the night light isn't very good. It seems when you select one of the sunset to sunrise times, there's a hard coded 30 minute transition. It should at least transition such that the night light is on by sunset, not transitioning at sunset. But it really should just be more configurable
Yes, in "Sunset to sunrise" modes, it starts transitioning when the sun begins to go down, and finishes once the sun is fully down. It's not hardcoded to 30 minutes; it actually does track the sun (as accurately as timezones allow, at least). In "Custom Times" mode, you can change the transition duration.