Overview

Sullivan & Cromwell’s April 2026 apology to a federal bankruptcy judge was the incident that made international headlines. But it was far from an isolated event. It was the latest and most high-profile entry in what has become a documented enforcement wave sweeping U.S. and international courts.

Researcher Damien Charlotin, who maintains the most comprehensive public database of AI hallucination cases in legal proceedings, has now catalogued over 1,353 such cases globally — with the pace accelerating dramatically in early 2026. He has described the current rate as reaching “ten cases from ten different courts on a single day.”

U.S. courts imposed over $145,000 in sanctions for AI hallucinations in legal filings during Q1 2026 alone, with a single Oregon case reaching a record $110,000 penalty.

This article documents every major incident from the past several months, what went wrong in each case, and what the pattern tells compliance professionals about where enforcement is heading next.

The Incidents, Case by Case

1. Oregon: The Vineyard Case — $110,000 Record Penalty

Attorney: Stephen Brigandi (San Diego) + Tim Murphy (Portland, OR) Court: U.S. District Court, District of Oregon Judge: U.S. Magistrate Judge Mark D. Clarke Date: April 4, 2026

This is the costliest AI hallucination sanction in U.S. legal history.

U.S. Magistrate Judge Mark D. Clarke imposed a total of $110,000 in fines and attorneys’ fees against two lawyers who represented a woman suing her two brothers for control of the Valley View winery and tasting room in Jacksonville, Oregon. Clarke ordered the lawsuit dismissed with prejudice, ruling that an AI tool had once again led human minds astray.

San Diego-based attorney Stephen Brigandi represented Joanne Couvrette, an Oregon woman who sued her brothers for control of their family’s winery, alleging elder abuse and wrongful enrichment and seeking $12 million. Because Brigandi was not licensed to practice in Oregon, Portland attorney Tim Murphy also served a procedural role in the case.

Three court filings contained 23 fabricated legal citations and 8 false quotations generated entirely by artificial intelligence. Rather than acknowledging the errors when they were flagged by opposing counsel, Brigandi “deceptively” deleted the false references and refiled his argument without explaining what had occurred. “Rather than a correction, Mr. Brigandi attempted a cover-up. He failed at both,” Clarke wrote.

The local counsel angle is particularly significant for compliance purposes. Murphy — primarily a landlord attorney — said he “did not write, review, research, sign or submit the briefs with AI citations.” The judge still sanctioned him, noting that the law “requires local counsel to provide more than an OSB number and a signature.”

Clarke’s language in the opinion set the tone for the entire enforcement year: “In the quickly expanding universe of cases involving sanctions for the misuse of artificial intelligence, this case is a notorious outlier in both degree and volume.”

Key takeaway for compliance: Signing a document creates liability for its contents regardless of who drafted it or what tool produced it. Local and co-counsel arrangements do not distribute or dilute AI accountability.

2. Nebraska: The First U.S. License Suspension

Attorney: Greg Lake, Omaha Court: Nebraska Supreme Court Date: Suspension ordered April 15–16, 2026

If the Oregon case was the largest financial penalty, the Nebraska case represents the most severe career consequence yet recorded: the first indefinite license suspension in U.S. history tied to AI hallucinations in a court filing.

In February 2026, attorney Greg Lake walked into the Nebraska Supreme Court to argue a divorce appeal. The justices stopped him 37 seconds in. Chief Justice Jeff Funke confronted Lake directly about the defective citations. A justice asked: “The elephant in the room is whether or not you used artificial intelligence. Did you?” Lake said no. He told the court he had been on his 10th wedding anniversary, his computer broke while flying, and he had uploaded the incorrect version of his brief.

The justices were not persuaded. Of 63 citations Lake made in his brief, 57 were flagged as defective — including 20 outright hallucinations and 3 entirely fabricated cases that did not exist in any jurisdiction.

Two days before the suspension was ordered, Lake sent an affidavit to the Supreme Court arguing against suspension. For the first time, he admitted to using AI to write the brief and called it a “grave error of judgment” for failing to be forthright with the court.

The consequences extend beyond the attorney. Lake’s client, Jason Regan, is facing $52,000 in opposing counsel fees while fighting for custody of his daughter — fees that are not reversed despite the sanctions against his lawyer.

Key takeaway for compliance: Misrepresentation to a court compounds AI misconduct into a candor violation — a categorically more serious offense. The cover-up is often worse than the original error.

3. Sixth Circuit: $30,000 for “Pervasive Misconduct”

Court: U.S. Court of Appeals, Sixth Circuit Date: March 2026 Attorneys: Two Tennessee-based attorneys

Attorneys paid $30,000 in sanctions in March 2026. The Sixth Circuit Court of Appeals wasn’t punishing sloppy research — it was fining lawyers for trusting AI models that fabricated case law, then confidently citing it in official briefs. The court also dismissed the case entirely because of “the pervasive misconduct” that rendered it “almost entirely frivolous.”

This case is notable because the Sixth Circuit imposed the largest federal appellate sanction to date specifically tied to AI-fabricated citations — and chose case dismissal as an additional remedy on top of financial penalties.

Key takeaway for compliance: Federal appellate courts are moving from warnings to case-ending sanctions. The cost of an AI hallucination is no longer just a fine — it can be the client’s entire case.

4. Southern District of Ohio: Contempt and Disciplinary Referral

Court: U.S. District Court, Southern District of Ohio Judge: Senior Judge Walter H. Rice Date: Q1 2026

Senior Judge Walter H. Rice imposed a collective sanction of $7,500 against two attorneys for AI hallucinations. He also found them in contempt and referred them to the Ohio Supreme Court’s Office of Disciplinary Counsel for what he called “the most egregious violations of Rule 11” he had seen on the bench.

The contempt finding is significant — it moves AI hallucination consequences from the civil penalty track to a criminal-adjacent proceeding. The disciplinary referral means two attorneys now face potential bar discipline on top of financial sanctions.

Key takeaway for compliance: Courts are beginning to stack remedies. A single AI hallucination incident can now generate simultaneous Rule 11 sanctions, contempt findings, and disciplinary bar referrals.

Court: U.S. Court of Appeals, Fifth Circuit Date: Early 2026

The 5th Circuit’s $2,500 sanction in early 2026 specifically involved an attorney who used vLex and Thomson Reuters’ CoCounsel to draft arguments, demonstrating that even commercial legal AI platforms can produce hallucinated output.

The court acknowledged imposing a steeper fine because the attorney didn’t accept responsibility.

This case carries a specific warning for organizations that believe using “enterprise” or “legal-specific” AI tools provides protection. The commercial pedigree of the platform did not prevent the hallucination, and it did not mitigate the sanction.

Key takeaway for compliance: There is no safe harbor from AI hallucination liability based on the reputation of the tool vendor. Verification obligations apply regardless of whether the AI is a general-purpose model or a purpose-built legal platform.

6. New Jersey: Repeat Offender, Double Sanction

Attorney: Raja Rajan, Cherry Hill, NJ Court: U.S. District Court (Philadelphia federal court) Judge: U.S. District Judge Kai N. Scott Date: April 27, 2026

U.S. District Judge Kai N. Scott sanctioned Raja Rajan $5,000 for submitting a court filing with AI hallucinations — having previously sanctioned Rajan $2,500 for errors in AI-written briefs. The Cherry Hill attorney was pressed on time so he says he took a “shortcut” when he wrote a brief filed in federal court on February 20. He wrote it using an AI chatbot, then asked a different bot to verify the citations were accurate. With the technology’s blessing, he filed the motion for a business dispute in which he represented his brother. Opposing counsel noticed six false citations.

The Rajan case illustrates an emerging and particularly dangerous failure pattern: using one AI to check another AI’s work. The verification step was performed, but entirely within the same failure-prone category of tool.

The judge warned she would refer Rajan to the state’s disciplinary board if he were to file a brief with AI hallucinations a third time.

Key takeaway for compliance: AI cannot verify AI. Cross-checking AI output with another AI tool does not satisfy verification obligations. Human review against authoritative primary sources remains the only legally defensible standard.

7. Gordon Rees Scully Mansukhani: Am Law 100, Twice

Firm: Gordon Rees Scully Mansukhani (Am Law #71, $759M gross revenue in 2024) Courts: U.S. Bankruptcy Court (Alabama); U.S. District Court (California) Dates: October 2025; February 2026

Gordon Rees — a firm that brought in $759,869,000 gross revenue in 2024 — found itself apologizing profusely to a judge and all parties, saying its attorneys were “profoundly embarrassed” after submitting a bankruptcy filing riddled with “inaccurate and non-existent citations.” The firm promised updated AI policies and a new “cite checking policy” after the first incident.

A recently filed brief in Huynh v. Redis Labs claims that Gordon Rees has again submitted a brief with AI hallucinations. In a motion to compel battle, despite having earned monetary sanctions and a warning that terminating sanctions could follow, the firm allegedly submitted more fabricated authority. “This is not aggressive advocacy or sloppy research. It is the submission of false authority to the Court in violation of counsel’s most basic obligations,” opposing counsel stated.

Gordon Rees had also received an additional reprimand in a December 2025 case in California federal court, where Magistrate Judge Carolyn Delaney wrote: “Counsel shall not file or otherwise present to the court any documents which contain AI-hallucinated citations or fictitious or non-existent legal citations.”

This is the most important repeat-offender case in the current enforcement wave. The firm updated policies after the first incident. The incidents continued.

Key takeaway for compliance: Policy updates in response to an AI incident are necessary but not sufficient. Without changes to the underlying workflow controls that actually gate document submission, policy language does not prevent recurrence.

8. Sullivan & Cromwell: The Incident That Went Global

Sullivan & Cromwell, employing more than 900 lawyers and widely regarded as one of the leading corporate law firms in the United States, issued an apology to a federal judge after submitting a court filing that contained inaccurate legal citations and other errors produced by artificial intelligence. The errors were identified by opposing counsel at Boies Schiller Flexner.

The S&C incident is unique in that the firm publicly disclosed having comprehensive AI governance policies, two mandatory training modules, and explicit verification requirements — none of which prevented the filing. It is the clearest documented example of the gap between AI governance as written policy and AI governance as operational reality.

For full analysis of the Sullivan & Cromwell incident, including the compliance framework breakdown, see our companion piece: When AI Hallucinations Hit the Courtroom: The Sullivan & Cromwell Incident.

The Pattern in the Data

Taken together, these incidents in the first four months of 2026 reveal several enforcement trends that compliance professionals should track closely.

Sanctions are escalating. The progression from $2,500 (5th Circuit) to $7,500 (S.D. Ohio) to $30,000 (6th Circuit) to $110,000 (Oregon) in a single quarter is not random. Judges are calibrating penalties upward in response to persistent non-compliance across the profession.

Career consequences have arrived. Nebraska’s indefinite license suspension for Greg Lake represents a qualitative shift from financial penalties to professional existence. This is no longer just about fines.

Repeat incidents at the same firm are now in the record. The Gordon Rees pattern — hallucination incident, updated policies, subsequent hallucination incident — is the precise scenario that triggers escalated judicial response. Courts explicitly note prior incidents when imposing new sanctions.

Commercial AI platforms are not a safe harbor. The 5th Circuit’s sanctioned attorney used Thomson Reuters CoCounsel and vLex — not a free general-purpose chatbot. Enterprise legal AI tools produce hallucinations. The product tier does not determine the verification obligation.

Associated and local counsel bear liability. The Oregon vineyard case sanctioned a Portland attorney who did not write, review, or submit the AI-contaminated briefs. He signed them. That was enough.

The cover-up is treated as a separate and more serious violation. Both the Oregon and Nebraska cases involved attorneys who initially misrepresented the origin of errors when questioned. In both cases, the misrepresentation drove the severity of the sanction more than the hallucination itself.

The Disclosure Trend: Courts Are Now Requiring It

Beyond sanctions, a parallel regulatory development is underway. Over 35 state bar associations have issued guidance requiring attorneys to verify AI-generated content, and multiple federal courts now mandate disclosure of AI use in filings.

This means organizations operating in regulated industries should begin treating the legal profession’s disclosure requirements as a leading indicator. If courts are mandating AI use disclosure in legal filings today, regulators governing financial services, healthcare, and government contracting are likely to follow within a 12-to-24 month window.

What the Tools Landscape Looks Like

It is worth understanding the scale of AI adoption against which these incidents are occurring. Harvey AI, backed by Sequoia Capital at an $11 billion valuation, is now used by over 100,000 lawyers across 50% of AmLaw 100 firms. Thomson Reuters CoCounsel, vLex, and Westlaw Edge’s AI features are deployed broadly across small, mid-sized, and large firms alike.

The hallucination incidents documented above span this entire spectrum — from solo practitioners using free chatbots to Am Law 100 firms with purpose-built enterprise legal AI. The tool does not determine the risk. The verification process — or its absence — does.

What Every Organization Using AI in Professional Work Must Do Now

The legal profession is the highest-visibility example of a broader phenomenon: AI being deployed in high-stakes professional contexts where output is submitted to external authorities as factual representation. The courts are the first sector to impose systematic financial and professional consequences for failures in that context. They will not be the last.

The minimum-viable compliance response for any organization deploying AI in regulated professional work:

Establish a verification standard that AI cannot satisfy itself. Any organization that considers AI-generated output verified because another AI reviewed it is not operating with a verification control. It is operating with an illusion of one.

Treat signing as ownership. Anyone who signs, submits, or attests to AI-assisted work product owns its accuracy. Contractual or organizational distance from the AI tool does not distribute or reduce that liability.

Build escalation protocols for prior incidents. The Gordon Rees pattern — recurring hallucination incidents at a firm with updated policies — is exactly what triggers the transition from monetary sanctions to case dismissal, contempt, and disciplinary referral. Prior incidents create a rebuttable presumption of systemic failure.

Prepare for mandatory disclosure requirements. Courts are already requiring AI use disclosure in legal filings. Organizations should begin developing disclosure frameworks now, before regulators in their specific sector formalize requirements.

Track the sanctions database. Damien Charlotin’s publicly available database of AI hallucination cases in legal proceedings is the most useful early warning system currently available for understanding where enforcement norms are heading. The database has been cited in several court decisions addressing hallucinated material and is now tracking over 1,353 cases globally. If a tactic is appearing in that database today, assume your sector’s regulator is reviewing it tomorrow.

Sources: ABA Journal, Philadelphia Inquirer, Above the Law, Yahoo News/OregonLive, WOWT Nebraska, The Ethics Reporter, CRE Legal Risk / AI Consulting Network, Helsell Fetterman legal blog, Damien Charlotin AI Hallucination Cases Database. This article is for informational purposes only and does not constitute legal advice.