VLX3 settings - input level resets

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The vocal input level setting is changing on its own.  My VLX3 MIDI is connected via USB, and I send MIDI to it to control vocal harmony via a MIDI file player in Gig Performer from my Macbook.  I have MIDI set in the VLX3 to listen on its own channel, 13.  If I leave the settings screen open, I can watch it change.  Is it possible that the VLX3 settings can be controlled via MIDI, and is being changed by some CC sent to it?  I looked in the manual at the MIDI CCs for the VLX3, and I did not anything for the input level.