Since it is a high gain pedal so and perhaps not completely up boxed up (pictures) with all common grounds 100% secure with no cold solder joints that is a sure sign there is a ground issue. We have all experienced the same thing which indicates what to do next.
Touching the ground to remove noise indicates you are grounding the circuit where it lacks.
Could even be too much over spray where the jacks make a connection to the enclosure. Guessing here.
If so scratch away some paint from the jack location on the inside of the enclosure.