@TheBeatnics I'm no expert in electronics, but I couldn't resist chiming in. I only have experience with a standard PODxt device, but it doesn't usually switch to this screen without toggling the "edit" button. Losing the tone like that, does it sound like you get into the tuner?
My point, really, is that it is probably not a single control malfunctioning, but may rather be a current spike or a drop in current that messes with the board. I would advise you to look for a dead/dying capacitor. I've never had to open a POD myself, but given their age, I would definitely look at capacitors.