I agree. Looks like IR reflection or IR bleed. You'd be able to figure out which by taking the camera a few feet away from the building at night, out from any kind of obstructions or trees, and pointing the camera straight up at the night sky. If the image stays foggy like that, it's probably IR bleeding internally in the camera. If the image clears up, it was from a problem with the camera location. Either IR from the camera reflecting back from a nearby surface, or perhaps IR from another camera or illuminator.