I think I am having the same issue.
What has been happening with me is as soon as I touch the expression pedal, it begins to adjust the FX. For example, I have a preset tone already set up. I will touch the volume pedal, and the screen will indicate that I've just adjusted the tone. Let me explain further.
1. I select the tone of my choice. Screen will read "06C American Clean"
2. I touch volume pedal
3. Screen indicates I've adjusted the preset and will change to "06C. American Clean" along with the red volume circle turning white and moving like I just turned the FX knob.
Weird. Not sure if this is the issue you're having, but I think it's similar.
