Qu drive interference (v1.9)

We have been using a Qu-24 at church for around 6 months and today was the first time that an audible sound is heard on the mains every time that the Qu drive is accessed. I have tried powering the mixer off, moving the cables away from the mixer and using another drive, but is still prevails. Here is a short clip of the noise heard:
https://www.youtube.com/watch?v=fedIHKnPhRY

We upgraded to v1.9 a few weeks ago but it is the first time that this happens. I do not know if it is related, but previously we had a case where the drive was not detected and the led only flashed very dimly. Rebooting the mixer helped. This happened right after upgrading to v1.9

Do you have idea what could be done to fix this?

André

Try muting ST3. There were some early models which have some issues with open ST3 input.
Difficult to hear in the clip with music on…

Boards should be rebooted after firmware upgrades - all sorts of slightly odd display things happen.

The QuDrive ST3 interference is fairly well known, a connected input or muting the channel are both typically curative.