My Spider IV 120 is almost doing the same thing, except that the effects will change at random while I'm playing and nowhere near the amp - it will do it even if I haven't touched the Master Volume Knob. Obviously this is a HUGE hassle and considering I've read a lot of these problems on the net and these forums, it's obviously not a specialized issue as many people have experienced this. I'm not going to ship it back, so I guess I'm stuck with a big fat practice amp (as I can no longer trust it for live gigs after the last embarrassment) that acts like an ADHD child with a side order of Oppositional Defiance Disorder.
Nice. Maybe I should hire an EA for my amp.
Figured for $600 I'd get a decent amp that worked.
Answer: Nope.