I am not a lawyer, but I explore these questions by imagining an existing situation with a human. If your friend gave you code to publish and it turned out he g

I am not a lawyer, but I explore these questions by imagining an existing situation with a human. If your friend gave you code to publish and it turned out he gave you someone else's code that he had memorized, would you be breaching copyright? The answer in that case is plainly yes, and I think it would be no different with an LLM. Substituting a human for a computer changes some aspects of the situation (e.g., the LLM cannot hold copyright over the works it creates), but it's useful because it leaves the real human's actions unchanged. However, for more complex questions that interact with things like work-for-hire contract law, you may need to take a more sophisticated approach.