I’ve had a few severe volume knob issues over the years from shipping and regular use.
Whether from shipping or regular use, the system that holds the knob in place from the INSIDE of the amp untightens, gets loose, gets knocked around over time.
I was was able to fix 2 of these issues by taking off the amp cover, inspecting it, and resuming the system inside the amp to hold the knob properly.
The other time, I could not fix it it, and had it serviced by a local audio repair shop (it didn’t require that I send back to the amps to the original manufacturer).
If your Pathos is a v1, then it is a good 10 years old, and susceptible to volume knob issues/disconnection. If you bought this used, then a pair of hand may have already been playing inside the amp, and who knows WTF they did to it.
But it this may just be wear and tear on an old amp, and to some degree, is to be expected.
Best