Retro Synth Aftertouch going haywire

I have been rehearsing a MainStage performance with the Alesis Vortex Wireless keytar, however the Retro Synth I am using seems to get hung on activating the LFO/vibrato as if I am activating via Aftertouch or Modulation, even though I am not. The set I am using contains 3 patches. 1) Soft Pad 2) Electric Piano 3) Retro Synth (Simple Analog Lead). There is a certain point in the song, where after switching between all three of these, when I return to #3, the LFO/vibrato is to the max even though I am gently touching the keys and not using the mod wheel (I can tell because the sound is "wobbly").

How can I avoid the LFO/vibrato activating erroneously? I tried going through the setting of the retro synth and using several combinations. One idea was to deactivate the aftertouch - however the only way I could see to do this was to create a control in layout mode that would block the channel pressure message, which unfortunately means it removes all velocity sensitivity. I researched the Vortex Wireless manual and there is no way to disable after touch to my knowledge. I've tried both with the accelerometer on and off and still have the same problem. Any guidance as to why the modulation/aftertouch is being activated when I'm not sending these messages would be helpful.

Changing the LFO to "Mod Wheel" didn't have any effect on aftertouch triggers.

Any setting I choose alters the sound in some way when aftertouch is triggered. I cannot seem to disable it here.