Had this problem once before, but uninstalled all my Nikon viewing etc software and it cleared up. Haven't changed anything since then, but it just started doing it again. Photo looks normal in Adobe camera raw, but when opened from there into CS6 it becomes highly color banded and cartoonish looking. On some pictures it's only happening in the brighter, highlight areas, in others the whole picture is affected. I'm using a high end Alienware computer and didn't have any issues for about the first year, my graphics card drivers are up to date, will check on monitor drivers next I guess.
What are your Color Settings?
Please provide screenshots to illustrate the issue and set the Status Bar or Info Panel to display the Document Profile.