Risk to the writer: Structural
Not a drafting failure. US copyright requires human authorship, so purely machine-generated expression is not protected and there is nothing to assign. The clause does what it says and assigns the copyright that exists. If most of the expression came from a model, the client has bought a thin compilation and a set of promises.
Nothing you can fix by wording alone. Manage it by ensuring enough human expression is in the deliverable that the assignment has something to bite on, and by disclosing what was generated.
General information, not legal advice. Have a solicitor or attorney review anything you intend to sign.