Tom,
There is several things going on here. One thing is that you weren’t in calibration mode, you were in the mode that tells you what software version you have…hence the flashing green light. The tap light will pulse normally in calibration mode, depending on where the depth knob is set.
When testing the pedal, please make sure you are using a guitar level signal. It sounds like you might be using a very hot signal which could give you different results than what I’m expecting. For an actual number use .1Vrms (100mVrms).
Are the sticky knobs physically sticking or are they just not responding when they are being turned? If it’s a physical resistance at certain points then you should make the knob setting jig from the manual and re-set them. You can remove the knobs for now, if it bothers you…use a fine tip sharpie marker and draw a line on the pot shaft where the knob pointer should be so you have an idea of where in the rotation it is.
Since you didn’t build this pedal, please make sure all the solder joints are good…don’t trust other people’s work. On principle, I would just re-flow them all. In my experience most, in not all, of these problems could easily be caused by bad solder joints, particularly the weird volume issue.
Try calibration mode again and let me know what you find.
-Brach