I've seen this characteristic (much less pronounced) on 1931-S cents. Never gave it much thought. Perhaps the "step" is caused by die failure as it is not a clash.
It's a form of die damage that's seen on the reverse of wheatback cents from 1917 - 1945. It can be bilateral or unilateral, but is located approximately where you see it on this coin. It can take the form of accidental die abrasion, a die dent, or a combination of the two forms of damage. The feeder/ejection.mechanism is the most likely culprit.