Was you D700 shutter speed also 1/250s? The lights are cycling at 1/60s so at the fast shutter speed you have an opportunity to hit a "valley", you can see that the color temperature changed in these images also which also happens as the light cycle on/off.
Those of us that shoot slow shutter speeds in available light typically don't get to see this phenomenon. I do have a snow flake photo, falling snow in front of my house - under a single street light. If you look closely in that image the snowflake trajectory is interrupted several times during the frame by the 1/60s blink of the street light. You can almost calibrate the slow shutter speed by how many "dots" there are between the top and bottom of the frame.