Judge Slams Patent Lawyers for AI-Hallucinated Cites in Brief

Attorneys representing patent owner Lexos Media IP LLC have to explain themselves to a judge after filing a brief containing artificial intelligence-generated quotations and legal citations in an infringement suit against Overstock.com Inc.

Judge Julie A. Robinson’s Monday show-cause order told Lexos’ lawyers to explain what AI platform was used to assist in their writing of a July pre-trial filing and inform the court if their client was aware of their use of generative AI.

The Lexos brief, which argued against excluding testimony from an expert witness, was replete with defects including "(1) nonexistent quotations; (2) nonexistent and incorrect citations; and (3) misrepresentations about cited authority,” Robinson wrote. In a separate order Monday, Robinson barred Lexos’ legal team from adding any new material to the offending opposition brief, only allowing them to strike “fake and incorrect” AI-generated cites.

The misstep makes Lexos’ attorneys the latest in a growing number to have gotten themselves into hot water by using generative AI in their drafting of court filings.

Houston-based Sandy Seth, a Lexos attorney, filed a declaration in August saying he authored most of the document but failed to check the AI cites before filing. Seth explained that he’d been caring for two dying older relatives while he was working on the brief, “overlapping personal situations” that “weighed heavily on my time.” Overstock had flagged the document’s issues in a reply brief.

Seth said the filing was nonetheless “inexcusable,” and he offered his “sincere and unqualified apology to this Court, to my co-counsel, to opposing counsel” and to the parties in the case.

“While the Court is heartened by Mr. Seth’s admission that he used generative AI without validation and by his remorse, it cannot find that a ‘do-over’ is warranted here,” Robinson wrote, declining Lexos’ request to supplement the faulty filing.

Buether Joe & Counselors LLC and Fisher Patterson Sayler & Smith LLP also represent Lexos. Overstock is represented by Fish & Richardson and Embry Law LLC.

The case is Lexos Media IP LLC v. Overstock.Com Inc., D. Kan., 2:22-cv-2324, order to show cause 12/15/25.