I don't know if is intended, but it seems like the iron golem crack textures are sort of mixed-up. The first crack stage looks similar to the original 2nd stage with some little pixel changes. The 2nd stage looks lIke the original 3rd stage with a little less cracks. The last stage stays the same. (The original first stage is nowhere to be found.)
Forward-resolved towards MC-166850, as it's already been assigned to a Mojang employee.