Soldato
The arm's mounting section to the display uses screws and some might be out of alignment or too long (by a tiny fraction). This might have a bad contact at the back of the display and anything that's run on mains nearby might be leaking small amounts of current through and this might be screwing with the display internally from something that's not earthed/protected properly inside. This can be LED lights, speakers, etc.
The arm doesn't screw directly into the monitor, the monitor comes with an adapter - the arm screws into the adapter, the adapter clips into the monitor where the default stand would go: