Sounds like a bad pot, or it could be a cold solder joint.
I’ve never see a pot damaged by bending a lug (expect for breaking the lug off).
You don’t need to get real fancy with the cap discharge probe, a 1 watt resistor would do, in fact, if you unplug the amp, put a test lead (jumper wire) without a resistor from ground to the plate (pin 1) of V1 and turn the amp to the “on” position (be sure it’s unplugged from the mains), the caps will drain in about 20-30 secs. You can short the caps one by one to ground after that just to be extra sure that there is no energy left. I usually just clip a grounded test lead to a plastic handled screwdriver and touch all caps for a couple of seconds. I haven’t been bit yet (hey, did I just jinx myself?).