Line 6 Spider II Half Stack 150w head and 4x12 Cab - weird issues with switching channels. Despite being very careful to hit only 1 switch (so please don't suggest that I'm hitting 2 switches at once) I am having a problem with my head suddenly cutting all noise and lights going crazy all over the unit. Looks like it's trying tuning mode but sometimes it sounds like it's going haywire, cycling through various effects, especially the smart control FX effects. Is this a known issue? Something electrical with the fbv express mk ii?