From playing around with ChatGPT and LLama2, this is most likely because it ingested that poem and regurgitated it to you based on the context of your conversat

From playing around with ChatGPT and LLama2, this is most likely because it ingested that poem and regurgitated it to you based on the context of your conversation. GPT is smart and creative but it will only give you what it’s ingested. When experimenting with story ideas for a popular IP, it gave me specific names and scenarios which I would then Google to see that they were written already, and it was just restating them to me based on the context of our conversation as if it were an original idea. These things are more tools than thinkers.