The +/QUAL button on the back of the camera is easy to accidentally press instead of WB or ISO. If the +/QUAL button is depressed, the control wheel quickly cycles through other image quality selections. I've made a similar mistake myself - its easy to do if you are used to managing controls through the viewfinder. Given that ISO and WB are in a different location on the D800 vs. the D600, the error is easy. The +/QUAL button is also the zoom button for viewing in playback - again a likely source of error if you scroll through images when viewing.