you recognize the difference in these gif-animations, which consist of only
four frames each?
what causes the difference in motions, whereas the flickering seems to be the same in both?
when managing to cross the eyes and converge to one image, there will be no rotation at all!
alternatively adjust animations to your pupillary distance, then converge eyes behind display
click the image below repeatedly for originals (details are segments from the left upper edge)
possibly you will find the solution in the different black and white slow motion