It sounds like you have the long-press function enabled. Normally this function is used with the shimmer effects to switch between shimmer and reverb only. This is accomplished by simply turning the right-hand knob (shimmer level) to 0. If you have this function enabled with another effect loaded, it will seem like the right hand knob doesn't work.

Also, remember that the long-press function (like tap tempo) does not automatically go away when you load in a different effect. You need to disable this function on the pedal itself as follows:

  1. Remove power from the pedal.
  2. Hold the footswitch down, and reapply power while keeping the footswitch held down.
  3. If using the ExP Controller, change to the effect slot you want to configure.
  4. Turn the right-hand knob fully counter clockwise.
  5. Release the footswitch.

The long-press function is now disabled.