GAIA-2: When I assign a CTRL knob parameter of MFX or REVERB DELAY to MOTIONAL PAD, a message "Not Available!" Appears.

Depending on the effect type and parameter settings selected, the CTRL knob parameter cannot be assigned to the MOTIONAL PAD.

For details, see "MFX parameters assignment list" and "Reverb/Delay parameters assignment list" in the GAIA-2 Reference Manual.