UR222C sends out some disturbing noice

Hi
On my mixer i can see the noice comming out from the UR222C
I closed as test at first all the other audio…and the last culprit seems to be the UR222C.
If i open maximum volume it looks like a heartbeat comming out.
Any suggestions?

I already tried all the power…
not yet the ground isolation.
Looks like it is inside the unit?

cheers
smoker