What does it mean that the keychain is broken?

It means the key chain is broken! It doesn't matter, you have to ask what it indicates. Isn't this a common thing? If it is new, it is broken, indicating that the quality is not good. If it is not new, its service life is over. You need a new one. It's that simple! Don't be idle, are you tired? Look at simple things as complicated, and relax!