You know how you can select some of them and disable them?
You can try cutting one and see how it works but I do think it's missing the line. Could be wrong tho.
Why? No idea. Are you sure you don't have some sort of line issue in your file? I'm just guessing here. No real reason why it would work and then wouldn't.
You could try "reprinting" it so it creates a new cut file. See if it fixes it or not.