I think I have had the same issue. I'm not sure if it happened when switching presets but that's very possible.
I was editing multiple presets I had imported from my OG Helix. They all needed the same change, so i wasn't playing the presets.
Just changing some settings, saving, and moving on to the next preset. Then discovered there was no sound when starting to play.
I filed a ticket. Support wanted to know exactly when it happens, but I had no clue. Now I do, thanks!