Did you ever find a solution to this? I can confirm that with the effects turned off, the expressional pedal controls the volume of the sustain/synth engine, and there doesn’t appear to be a way to reprogram it.
I was wondering this as well. In fact the manual doesn’t document that the expressional pedal does anything when the effects are off, but it’s as if the EXP controls the EFFECT knob, which is not one of the 7 knobs it normally controls. So basically if you leave the expression pedal at full heel and turn effects off, you will never hear a sustain sound, which is not obvious (or that desirable IMO).
It would be great if heel and toe settings could be stored with the effects off, for example only changing ATTACK and DECAY with the EXP pedal. Any chance we might see this added?
Mode1; play and freeze something.
Switch to mode 5.
Switch back to mode 1.
If effects were off in this last switch then nothing is heard.
If effects were on in this last switch then whatever was previously frozen is heard (like a fade out).
I can confirm this as well. It appears to be a bug, and only happens when switching from LIVE EFFECTS to MOMENT mode, and only if the effects are on, as you describe. Is there any chance of a firmware fix?