My D5100 doesn't change color temp with ISO. I ran two sets of tests with different lighting.
First when setting the scene to Dusk/Dawn the camera wants to go to Auto ISO. However it can be over ridden to whatever you want.
My first test was in lighting that was mostly daylight. I used ISO 200 and ISO 500. The color temp stayed at 4550˚K.
My second test was in lighting that was mostly Red/Yellow as you'd see during sunset. Auto ISO set the exposure at ISO 800, I set ISO to 160 and then again at 640. For all three exposures the color temp stayed at 4550˚K.
However I don't have the light that you shot at so I don't know how my camera would react under your condition.