It has to have something to do with certain scene files. I create a brand new scene and bring that same image in and I do not have the color gain going back and forth between 1.0 and .5 every time I go to the color channel.

But if I open any of the scenes that have that happening then not only does it toggle in that scene but every scene I open from that point on.

Whatever it is it appears to be embedded in the scene file itself because wiping the maya folder does not clear it.