Stupid Question: Audio interference coming out of speakers after OS update. Is this possible, or is it an external influence?

At the risk of sounding stupid, I can't seem to figure out what's causing this problem.

I have a USB audio interface plugged into studio monitors. It works perfectly, with no interference humming out of the speakers, when plugged into my legit MBP, but not when I plug it into my desktop. Whenever I get the USB cable close to my computer (specifically, when it comes in contact with the ports), it starts to hum from the speakers and make ugly noises. This wasn't the case a few weeks ago, before running some OS updates.

Now, given how electricity works, I am assuming that the touching of the USB cable is completing a circuit which is giving feedback, and is likely a hardware issue... but... why would this have changed after running some OS updates? It seems bizarre.

Is there any way that this is happening due to some audio signal output being altered under the hood, or is it really just some new, external factor that is jacking up my monitors?