I've had an issue with Mission SP1-L6H Expression Pedals, specifically in regard to volume blocks. When assigned as a volume pedal (in my case, it's connected with a single TS cable to EXP1 on Helix Rack), A 100% parameter value will drop to 0% randomly without the pedal being touched. This, of course, results in a complete loss of output, which has made for some pretty awkward moments on stage. To troubleshoot, I used multiple brand new cables as well as a few different Helix Rack units. After determining my first Mission pedal was the issue, I got a replacement from Sweetwater. To my surprise, the new unit had the same issue. I reached out to Mission, but they said there weren't any other reports of this happening. At this point, it's too late to get a refund, so my Mission pedal is just collecting dust now. I recently purchased a Dunlop DVP3 Volume (X) and I'm using it (Polarity reversed) with my Helix and I've had no issues whatsoever. It's very possible that I just received two faulty Mission units, but I have a feeling it's just an inherent issue with the pedals. I'm hoping someone could help shed some light on the issue.