Aperture screwing with brightness in full screen mode

For some reason whenever I go into full screen mode Aperture keeps adjusting the brightness of my images. Every time I do anything it first looks "normal" then the brightness gets jacked up a few percentage points. When I turn on the Loupe, the image shown inside the loupe is darker (as it should be) as this odd "auto brightness" effect doesn't show up there. When not in full screen mode this doesn't happen. Saving the photo results in the correct image as well. So long story short this is only happening in full screen mode.

I tried disabling the "On screen proofing" but it doesn't seem to have an effect. This is driving me nuts because I have no way to see the ACTUAL image until I save it! Thanks for any ideas you may have.