Each time when in general chat you click the Add to notebook button, a new card with the name of the chat is created and then the chat answer is linked to that card. So, you end up with multiple cards with the same name.

I would expect when a new answer in the same chat is created then the Add to notebook will append the answer to the already existing card - or maybe allow us to pick "Add to chat's notebook" and "Add to a new notebook".