If I only had one guess, it would be by a blade all right...a perfect cut.

But not long ago some collectors were reporting quite a few of a certain new issue were coming out that way. There were a few guesses made as to why.

I just surmised it was metal stress that occurred as the "slugs" were cooling down when made and the resulting cracks in the finished strike were caused by, not the die directly, but when the die hit the slug and all the fractures weren't "squished" to oblivion.