Did not note the horizon line was tilted relative to the other two until I posted. Did not have the time to correct it. I have since coordinated all three versions in the files so the tilt matches. At the time of shooting it was hard to select the correct level as the granaries are tilted and the field is on a slight incline in all directions (the granaries are on the top of a small rise in the ground).
So the answer is bone idleness.