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Incident Tracker / United States (federal)

Lichfield v. Kubler; Netflix, Inc., No. 25-4135 (10th Cir.)

·US Court of Appeals for the Tenth Circuit·US-FEDWarning

Affirming dismissal of a defamation suit over a Netflix documentary, the US Court of Appeals for the Tenth Circuit noted that the appellant's brief cited a case that does not exist and misdescribed two others. Assuming generative AI was responsible, the court issued a published admonishment but stopped short of the sanctions it imposed in Amarsingh v. Frontier Airlines.

Court
US Court of Appeals for the Tenth Circuit
Date
2026-07-27
Who used the AI
Lawyer
AI tool
Not identified in the record
Conduct
Appellant's counsel from Hepworth Legal of Bountiful, Utah, cited a nonexistent authority and mischaracterised two real cases in the opening brief of a defamation appeal concerning a Netflix documentary. The court assumed generative AI was responsible.
Outcome
Warning
Penalty
No monetary penalty recorded
Regulatory outcome
No separate regulatory disposition recorded
Status
Verified against listed sources
Last checked
2026-09-03

What was fabricated or misused

  • Opening Brief at 39 — one legal authority did not exist; the opinion did not name it
  • Opening Brief at 43 — one case was characterised in a manner wholly unsupported by the text; the opinion did not name it
  • Opening Brief at 45 — one case was characterised in a manner wholly unsupported by the text; the opinion did not name it

What the court said

“In his Opening Brief, Lichfield included citation to a legal authority that does not exist, see Op. Br. at 39, and characterized two cases in manners wholly unsupported by the text of the opinions, see Op. Br. at 43, 45.”
US Court of Appeals for the Tenth Circuit, p. 43
“It should go without saying that a bare-minimum reasonable inquiry will ensure legal authorities cited in papers submitted to the court actually exist, and the quotations or propositions attributed to them also exist.”
US Court of Appeals for the Tenth Circuit, p. 44
“Although we assume the use of generative artificial intelligence led to the misrepresentations of legal authority, the brief here had significantly fewer errors than in Amarsingh.”
US Court of Appeals for the Tenth Circuit, p. 45
“The missteps in this case do not merit sanctions.”
US Court of Appeals for the Tenth Circuit, p. 46

Timeline

  1. Published opinion recorded a nonexistent authority and two unsupported case characterisations.
  2. Court noted reply conceded several citation errors but no corrected brief was filed.
  3. Court credited a notice of errata filed after oral argument questioning.
  4. Court affirmed dismissal and warned that the brief failed Rule 46.5.

Why this case matters

Lichfield marks the warning end of the Tenth Circuit spectrum. The panel found a Rule 46.5 failure, assumed generative AI caused the misstatements, and still declined sanctions because the brief had fewer errors than Amarsingh and counsel filed a notice of errata after argument. Unlike Scott or Barteca, there was no money sanction or disciplinary referral. The record is useful because it states the baseline duty in published form: existence, quotation, and proposition checks are part of even a bare-minimum inquiry.

Practice note

If an appellee identifies a nonexistent authority, file a formal errata notice or corrected brief before argument, not only a reply footnote. Under Tenth Circuit Rule 46.5, the signer must confirm that each authority exists and that the quoted language or legal proposition appears in the source, regardless of the drafting tool used.

Primary sources for this incident

Related regulation records for this incident

No related regulation record has been linked to this incident yet.

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Cite this record

SafeLegalAI Global Legal AI Incident Tracker, “Lichfield v. Kubler; Netflix, Inc., No. 25-4135 (10th Cir.)”, safelegalai.com/tracker/lichfield-v-kubler (accessed 2026-10-07). Data: CC BY 4.0.

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