I have tried to duplicate it with all the same first settings, both on the sky at home, and in the dark closet... without being able to see it again. VR and AF off everywhere. Whereas first time, there was no getting away from it. The sky in the city next night was at least four stops brighter, white at same exposure, but the closet was black (and the picture was black). No hints of red. One difference was about 30 degrees F cooler the first time. Another difference was first time, the 70-200 was not mounted on its foot, but instead hanging from the camera mounting (but aimed generally up steeply).
It is a mystery to me, no apparent source, made stranger because I could not duplicate it next night. I have no clue, but VR senses motion, or vibration, or something, and I wonder how VR could use IR? But VR was off.