My Helix is having an issue. Sometimes when I am playing through headphones, the sound gets thin and low, and kinda sounds like mono. If I rock the expression pedal forward kinda hard or tap the top middle section of the Helix kinda hard, the sound comes back. I played it off as maybe something to do with my headphones or maybe even the headphone port, but the other night at practice I was playing mono out to FOH, and headphone out to my Alto ts210. At certain times the same thing would happen from both ports, and I would have to kinda kick the Helix to get it back. I haven't really ruled out bad cables at this time, but since it has happened multiple times with the headphones coupled with different guitar cables, I'm starting to think I have a problem with the Helix. Anyone else having this issue?