IMO, this is not a WB issue. And I must point out, my D600 does NOT do this while set to the same ISO and WB and even my venerable D200 does a better job at it's max ISO, (I have shot this room several times before without issue).
Back to my point. Look at the shots. The center of the images has fine WB. The edges, however, are purpleish, (like I say, I think this is sensor amp noise). It appears something is going on with the sensor at this high ISO and low light. I have shots from the lobby of the hotel where you can see the purple color as well, and it was a much more brightly lit environment.
"Extraordinary claims require extraordinary proof " - Carl Sagan