Devices are greyed out after some time

Hello Folks!

We are running the “stable” version of The Dude since years back and it has always served us well.
However, recently a few devices has been greyed out, all monitored services are grey also when looking on them.
Like CPU, PIN, DNS, DISK all are greyed out.

If I delete the device and add it again it become green for some time, then again it becomes greyed out.

Anyone who have seen this from before ?

Look in the device settings if there is maybe a wrong parent set. If the parent is not reachable the device is greyed until the parent is reachable.