It's a little hard to explain, but incuse design elements will look like they are hub doubled on a coin when it comes to
Machine Doubling. If you think of everything backwards (which is required for incuse lettering), it makes sense.
Anyhow, even notching can show up on incuse elements in
Machine Doubling.
Your coin is a slight case of
Machine Doubling, and I disagree with Coop that it would show someplace else.
Machine Doubling does not have to show on other design elements to be what it is. I've seen
Machine Doubling on a mintmark only with the remainder of the design completely unaffected.