The Gemini will treat a dual sustain pedal as expected in Single and Split mode, where the layers can individually be put in sustain mode.
However, in Dual mode any of the two sustain pedals will sustain both of the layers.
Tried two different pedals, a VFP2/15, and a Boss FS-7.
@klontart this is expected behaviour. @DDS please can you log individual sustain pedal control in Dual mode as a feature request. Just a reminder we do not offer technical support via the forum but you can contact support@udo-audio.com.
I also have this issue and would consider it a bug the way it currently works!