At first I did not believe my D800E had any left focus issue until today. A week ago my D800E was sent to Nikon El Segundo for sensor cleaning and while its there I had nikon look into the focusing operation. To my surprise Nikon did a fine job, the images now are much more crisp (Flickrs does not help in this matter). The lens seem to catch focus quicker!
Your statement confuses me. You did not believe you had a problem? So if you didn't have a problem with the camera in the first place , did they really fix it?
I just completed some autofocus test on the camera left, center and right side. It did well and I feel nikon has improve my autofocus system on the D800E. BTW, the stop light sign was shot with a nikon 24-70 @70mm f2.8.
I have been to Nikon El Segundo a few times and so far have not had a bad experience.