This is an odd problem if you're using a standard lens. I've been told that it's called photo chromatic aberration and it's a fairly common problem with inexpensive big (600-1200mm) telephoto lenses.
If it's happening with a good quality standard lens this suggests that there may be a problem with the autofocus not being quite set when you take the first shot then being fully adjusted by the time you take the second shot.
I'd suggest contacting Nikon support at www.nikon.com to see what they suggest. Be sure to provide them with information about what kind of lens you are using and what the light conditions are.
Answers & Comments
This is an odd problem if you're using a standard lens. I've been told that it's called photo chromatic aberration and it's a fairly common problem with inexpensive big (600-1200mm) telephoto lenses.
If it's happening with a good quality standard lens this suggests that there may be a problem with the autofocus not being quite set when you take the first shot then being fully adjusted by the time you take the second shot.
I'd suggest contacting Nikon support at www.nikon.com to see what they suggest. Be sure to provide them with information about what kind of lens you are using and what the light conditions are.