Interesting problem. After I adjust my images in the Develop mode, I check my histogram to make sure my highlights are not blown. All looks good. Histogram looks great, image looks great, I am satisfied. I move away from the image and when I go more than two images away and return back to the image, my histogram has returned to being in the red again. If I only go one image away and return, it is fine. It's only if I go more than one image away will the histogram will change. As you can imagine, I thought I was going crazy and going back and forth on the images for awhile before I figured out what was going on.
My workaround has been to just use my eyes and not rely on the histogram. However it is annoying. Mind you, I am not doing major adjustments, my original exposure was just a click off and I am working on RAW files.
Any help or ideas greatly appreciated.