New D800 - Oil on the sensor after 150 pictures

My D4 had a few oil spots right away. Had it cleaned and they've not returned since.

However, this was a REAL and persistent issue with my D7000 which Nikon fixed under warranty. I must have had that camera cleaned about 6 times before I took it into Nikon's El Segundo facility. They fixed it without question (replaced mirror drive unit) and I had it back within 48 hours.

The D7000 was also back-focusing consistently, but they repaired that as well.