I suggest that the night picture might have its contrast and sharpness undermined by flare induced by the street lights which are present in the picture and maybe some other street lights and maybe some passing cars during the long exposure, especially if they passed with their front lights pointing toward the lens. Flare sometimes takes the aspect of a slight "light veil".

Just an hypothesis


Also, the night picture having being taken near the road, some heavy vehicle (truck, bus) might have induced vibrations that lasted for only a small part of the exposure, not enough to ruin sharpness but maybe enough to make it a bit soft.