Oh, I don't think any court would rule that using LLM generated code automatically infringes on the copyright of everyone whose text was used to train it, independently of the degree of similarity between the generated output and the original text(s).

But LLMs have a habit of sometime, and not too infrequently either, reproducing parts of their training material verbatim, as their output. As long as it's only sufficiently small "snippets" of text or code, it's unlikely to raise significant copyright concerns - but the fact is that it's not actually that rare that an LLM will replicate larger sections of text from its training material, spanning across many lines. What's more, LLMs don't advise you of this, when their output is a replica of a significant part of an already-existing, copyrighted text. But you'll be infringing on somebody's copyright, whether you know it or not, irregardless of whether you aquired the text from an LLM or elsewise. That's a big liability to accept in a large project, that frequently uses LLM-generated code. It would be a minefield.