My more heavily used D800 is showing permanent stickyness on the inside of the front grip, where the fingers curve in to grab the body tightly. The 'rubber' feels like it's slightly wet and soft. Wiping with isopropyl alcohol and household spray cleaners (which use butoxyethanol as an aggressive but dilute surfactant) lessens the stickyness, but it comes back strong after a while.
It could be a chemical reaction with the contents of human perspiration, and possibly also a physical reaction to being squeezed (compressed). The remainder of the camera body, and the entire other D800 body which gets used much less, do not have the sticky rubber.