EB16 Distortion - Occasional Hiss

Ok, this is weird. So when I run sounds through the Distortion effect, it works fine for a while, then all of a sudden, it will sound a little different... like there is a little hiss, and the stereo field sounds different. Then, it will just go back to normal after a random amount of time. Can someone explain why this is happening on my 2k classic?

thanks,
mackoftrack

Loose ribbon cable?