When I turn on the Secondary Correction in the CC, the picture goes green - as if I had slected a color and told it to change to green.   But I didn't. All I do is turn on Sec, and the scene goes mostly green - no color picked. What gives?

8.8.4, WIN7.

Just for grins, try dsiabling GPU effects (Settings->Render->Disable GPU Effects) and then go into the color correction. I'm not sure if this is related to the GPU bug or not, but it's a quick way to find out. If it's not, just go back into the settings and deselect the option.