The 50L has focus shift - as you stop down from wide open, if back focuses, but at some point (which is dependent on subject distance) the thicker DoF overcomes the back focus. So, if plotting the sharpness of the 50/1.2L based on autofocus (assuming it's AFMA'd normally, i.e. at f/1.2), I'd expect it to be sharp at f/1.2, then get progressively softer as you stop down until somewhere in the f/2.2-f/3.5 range, then get progressively sharper again, peaking at f/4 or f/5.6 then dropping again after f/11 when diffraction sets in.