Scratchy/Noisy volume knob on Audio Refinement Amp

I know that I've seen this topic somewhere before, but have not been able to track down a similar thread.

I have a six-month-old Audio Refinement Complete integrated amp, and during the last month or so I noticed that when I turn the volume knob in either direction, my speakers emit this scratchy sound, and the cones extend waaay out or waaay in, depending on which way I'm turning the knob.

The sound is otherwise fine... as long as I'm not turning the knob, I don't hear a problem.

Does anyone know what the deal is? Is this sound a symptom of other problems? Or should I just leave it be?

Thanks