Club Penguin Yellow + White Puffle Pin Bug!

While on Club Penguin today I was checking my pins in my stamp book only to see my Yellow and White puffle pins having the name undefined! Take a look below:

The yellow puffle:

The White puffle:

Why do you think this bug has occurred? Has it happened to you yet? Quick, check your stamp book! Leave a comment and tell me! ~Happyblue128