A phenomona call ed amp glow sometimes appears in extreme long exposures, but for the 5D MK III, its usually on a edge or corner. There apear to be other colored reflections in the water. with a super long exposure like that, the camera may see reflections that you do not see.
I can't help much with the other images, one shows a lot of CA, typical of a wide aperture lens. CA can make a image appear to lose sharpness.