Just got off the phone with Mesa, and he assured me there is nothing 'wrong' with the amp and that it is normal. I DO have the master all the way up so as to keep the gain down so the channel is as clean as possible in channel 2, so maybe that is the problem like dom mentioned. That is the only channel I have the master dimed on and also the only channel that has this problem.
I'll play with it some more and see if i can reduce the amount of swell (or surge) when switching channels. I'm not a huge reverb user, but I'd like to know that I can use it without worrying about the odd space station sound that is emitted.
Thanks guys...
Adam