This is not my area of expertise, but this flaw was of no surprise to me. I have seen similar miscuts. Do I have one in my amateur collection? NO.
Searching
ebay for the phrase, "
Stanley Steamer 2132 miscut" resulted in photographs of a few similar stamps.
Perhaps others will chime in with expertise. By the way, what is the plate number on the stamp? I cannot make it out in the image.