Gamma, and Mystery Light in Rendered View Mode

I noticed that after closing the Render Window after a Raytrace (not to the viewport, but to the Render pop-up and saved to a file) Render View Mode in the viewport seems to have changed its gamma to match the gamma settings I’d adjusted for the post processing of the Raytrace. Is this the way it works?

I also notice that a Rendered View responds if I change the intensity of lights within a model for a Raytrace. I’m not sure why, because my Render lighting is set to Ambient Occlusion. When I navigate within a view port those changes seem to be neutralized, so maybe this doesn’t matter.

I’m confused about how this view changes. Attached is a recent effect I’m seeing in a rendered View MOde detail window, where it appears that light from somewhere is covering a (non-existent) plane with glow. Not sure why this is, with lighting set to Ambient Occlusion. Not a problem if there’s no overlap of details If I have detail windows layered on a layout sheet, this glow on nothing will fade anything on which it overlays.