Brightness with transition time: transitioning brightness not visible unless ZHA is reloaded

For an automation I use a transition time of 2,5 hours to softly fade a LEDVance ZigBee bulb from 100% to 5% and then stays at 5% during the night. This works without any problems, but as soon as the automation calls the light.turn_on service the lamp shows 5% in my dashboard, while obviously during the first 2,5hours that is not correct as the bulb is still fading.

I thought this was expected behavior, but when restarting HA while the bulb is still fading I noticed that, after HA comes back online, the dashboard shows the correct actual percentage of brightness (say 38%) and then the brightness also correctly changes during the rest of the transition time until it reaches 5%.

I searched this forum but only found 1 similar post regarding Z2M which mentioned something about reporting. To make sure it is not a problem with the lamp, I also tested this with a Philips Hue bulb with a transition time of 5 minutes. This gives exactly the same result. Dashboard immediately shows the end-brightness. But restarting HA (or simply reloading ZHA) while the bulb is still transitioning does actually show the actual brightness and correctly shows it transitioning.

Is it somehow possible to always have this behavior?

nobody has run into a similar issue?