Mac mini M1 - internet slows or stops working when a USB device is plugged in to USB-A port

Just discovered something new - I recently bought an IKEA monitor stand. It's a metal base. The mini is on top of it, next to the monitor. If I put something else under the mini, like a book, this behaviour instantly stops. As in the webpage/Safari will not be reacting, then suddenly if I lift the mini or put something under it, it instantly loads. Works every time.

So there is something about it resting on a metal surface that is causing this.

Is this normal?

Solution so far: put something under the mini. (I prefer to keep it on top of the stand now because the ports are easier to access and because it seems to get a better wifi signal with that small amount of extra height.) Still, seems a bit odd.

But only with a USB device connected.

Wifi actually works better on the metal stand than where it was previously. So it is the combination of connecting a USB device (and only to one of the ports) and the metal surface that causes the problem.

So I don’t think it is as simple as saying the metal is blocking reception, when with all of the other ports it works fine.

does anybody know if this is normal and expected behaviour?