Risk to the writer: Moderate
The clause predates generative AI and was written about copying, not generation. It survives AI use, unlike the copyright assignment, because it is a promise about provenance rather than ownership. This is where agency money actually leaks.
Keep it, and add a sentence making clear that material generated by a model is disclosed rather than silently warranted as original.
General information, not legal advice. Have a solicitor or attorney review anything you intend to sign.