Hue - Things change from ONLINE to OFFLINE

Hello Friends of Home Automation,

ive got this issue since long time and until today i did not find any solution.

In events.log i sometimes (several times a day) find this line:
[hingStatusInfoChangedEvent] - ‘hue:ccc:xxx:y’ changed from ONLINE to OFFLINE: Die Hue Bridge meldet, dass die Lampe nicht erreichbar ist.

This means that the HUE Bridge is telling that a Bulb is not reachable anymore.

The exact bulb varies, so it is not the same all the time. Sometimes also several bulbs go offline (not in the same moment but like this morning with a delay of 10 seconds 2 bulbs went offline).

Also this applies to original HUE Bulbs as well as ZigBee-Floodlights.
Whenever some bulb is offline regarding OpenHab-Log, i still can operate them with Hue App. But OpenHab apparently does not control the “offline-bulb” anymore.

Is there any known issue or some hint i could follow and try?
I mean, i dont see a real connection problem between Hue Bridge and Bulbs as they usually work with Hue App. Only OpenHab “thinks” (?!) that they are offline?!

There are several threads with the same topic, you may find more information there.