The shadow movement wouldn't be easily detectable on Apollo 11, but as a matter of irrelevant fact it quite noticeably affects the photography in the J-missions, where the sun angle changed by about 36° over the course of the mission.

I've already had hoax believers try to pawn off photos taken days apart showing "anomalous" differences in shadow angles.

Perhaps I'm just being dense, but I'm not sure what a lighting discontinuity would be expected to prove. Sure, if there were an abrupt discontinuity it would suggest an edit, but continuity is not something from which the lack of an edit can be inferred.

I agree if you could show a very slight, very consistent shift in lighting angle over the entire EVA video, this would suggest having been legitimately taken on the moon. However the television camera is only planted for a little over an hour at its final position. The sun angle changes by only half a degree per hour, so I doubt that would produce anything observable.

While not useful for the video, you could examine carefully the LM shadow as seen from the cockpit, depicted before the EVA in Roll 40 and after the EVA in Roll 37. Roll 37 lacks a reseau grid, though, and the zero phase angle will make it difficult to locate the shadow by reference to terrain.