Maybe, but I feel 'Incomplete' does fine; and it saves 2 characters on the label. You can say it's Incompletely Punched, or that it's AN Incomplete Punched Planchet.
I find Incomplete Curved Clip as a bad descriptor of what actually occurred. Incomplete Punch is a better descriptor.
A very nice error. Congratulations. Really speaks for itself. Don't know why anybody bothered to slab it. Would love to be able to see it out of the holder.