Capital Standard, LLC, Tchentsov v. US Bank National Association, Bear Stearns Asset Backed Securities I Trust 2005-AC9

District Court of Appeal of Florida·Decided August 21, 2026·No. 2D2024-1392·Published

Opinion

DISTRICT COURT OF APPEAL OF FLORIDA SECOND DISTRICT

CAPITAL STANDARD, LLC; VLADIMIR O. TCHENTSOV, as trustee of the TF15529 Land Trust; and ANNA TCHENTSOV, as guardian for Oleg V. Tchentsov, as beneficiary under the TF15529 Land Trust,

Appellants,

v.

U.S. BANK NATIONAL ASSOCIATION, as trustee for BEAR STEARNS ASSET BACKED SECURITIES I TRUST 2005-AC9, ASSET-BACKED CERTIFICATES, SERIES 2005-AC9,

Appellee.

No. 2D2024-1392

August 21, 2026

Appeal from the Circuit Court for Pinellas County; Michael F. Andrews, Judge.

Kenneth H. Keefe of The Keefe Law Firm, P.A., South Pasadena, for Appellants.

Kathleen D. Dackiewicz, Sara F. Holladay, and Emily Y. Rottmann of McGuireWoods LLP, Jacksonville, for Appellee.

ROTHSTEIN-YOUAKIM, Judge.

Capital Standard, LLC, Vladimir Tchentsov, as trustee of the TF15529 Land Trust, and Anna Tchentsov, as guardian of Oleg V.

Tchentsov, beneficiary under the TF15529 Land Trust (collectively, Capital Standard), appeal a final declaratory judgment entered in favor of U.S. Bank National Association. We conclude that Capital Standard's arguments lack merit, and we affirm the judgment in all respects without further comment. We write, however, to sanction Capital Standard's counsel, Kenneth Keefe, for his rampant use of hallucinated citations to legal authority in his amended initial brief and subsequent reply brief and to explain the rationale for the sanctions that we impose. 1 It's been three years since the release of the widely publicized decision in Mata v. Avianca, Inc., 678 F. Supp. 3d 443 (S.D.N.Y. 2023), in which a federal district court sanctioned several attorneys and a law firm under rule 11 of the Federal Rules of Civil Procedure for, among other things, citing fake cases created by generative artificial intelligence (AI) in legal memoranda and then responding evasively when confronted with the issue. Since then, and as we have previously noted, see Clerk of Ct. & Comptroller for 13th Jud. Cir., Hillsborough Cnty. v. Rangel, 427 So. 3d 1069, 1071 (Fla. 2d DCA 2025), the danger of using generative AI tools in

1 "Two types of mistakes, or 'hallucinations,' are most relevant:

fabrications and inaccuracies." Malkeet Lnu v. Blanche, 177 F.4th 1014, 1024 (9th Cir. 2026) (citing Magesh et al., Hallucination-Free? Assessing the Reliability of Leading AI Legal Research Tools, 22 J. Empirical Legal Stud. 216, 221 (2025)). "Fabrications are instances in which the generative AI tool provides cases or quotations that do not exist at all." Id. (citing 22 Empirical Legal Stud. at 221, 230). "Inaccuracies are more subtle. . . . The generative AI tool might cite to real authorities but provide an answer that is legally or factually inaccurate or not supported by the citation." Id. at 1024–25 (citing 22 Empirical Legal Stud. at 221– 22). "Fabrications are the most notorious hallucinations, but inaccuracies may prove more dangerous to our profession in the long run. Inaccuracies are more likely to go unnoticed by attorneys and judges because they are not always susceptible to facial checks." Id. at 1025.

legal writing without reality-checking the results has been well documented in numerous opinions in state and federal courts across the United States, in legal publications, and in the national media. 2 It's been the ubiquitous subject of CLE courses and roundtable discussions of attorneys and the judiciary. What's more, it's been the focus of a mushrooming number of decisions from multiple Florida district courts of appeal.3 In short, at this point in time, it defies belief for a practicing

2 Damien Charlotin, a French attorney and lecturer in "legal data

analysis," has developed a database referenced by multiple courts that tracks court orders related to AI-hallucinations. AI Hallucination Cases, Damien Charlotin, https://www.damiencharlotin.com/hallucinations (last visited Aug. 7, 2026). As of this opinion, Charlotin has identified 497 cases in the United States involving attorneys' reliance on AI hallucinations. Id.

3 See, e.g., Avery v. Beauzil, 51 Fla. L. Weekly D1068 (Fla. 4th DCA

May 27, 2026) (barring a pro se litigant from future filings due in part to AI hallucinations in filings); Gleason v. Marcus, 432 So. 3d 1265, 1265– 66 (Fla. 2d DCA 2026) (cautioning on the dangers of using generative AI without confirming the results); Rodriguez v. Rodriguez, 51 Fla. L. Weekly D771 (Fla. 6th DCA Apr. 10, 2026) (ordering attorney to show cause why she should not be sanctioned for filing a petition for a writ of certiorari containing AI hallucinations); Gouveia v. Meridian Fin. Invs., LLC, 432 So. 3d 49, 50–51 (Fla. 4th DCA 2026) (warning a pro se party against using generative AI without verifying the results in any future filings); Hessert v. Hessert, 431 So. 3d 610, 615 (Fla. 6th DCA 2026) (ordering a party to show cause why she should not be sanctioned for AI hallucinations in her petition for a writ of certiorari); Russell v. Mells, 426 So. 3d 913, 920 (Fla. 2d DCA 2025) (referring attorney to The Florida Bar for AI hallucinations); Takefman v. Pickleball Club, LLC, 418 So. 3d 826, 826– 27 (Fla. 3d DCA 2025) (warning about the use of generative AI without verifying the results); Goya v. Hayashida, 418 So. 3d 652, 656 (Fla. 4th DCA 2025) (warning a pro se party who had filed a "counterfeit brief" based on AI hallucinations); Rangel, 427 So. 3d at 1071–72 (referring attorney to The Florida Bar for AI hallucinations); Gutierrez v. Gutierrez, 399 So. 3d 1185, 1188 (Fla. 3d DCA 2024) (imposing sanctions on a pro se litigant for submitting a brief that included "fictitious case law").

attorney to plead ignorance of the risks of relying on generative AI without double-checking the results. See Fletcher v. Experian Info. Sols., Inc., 168 F.4th 231, 235 (5th Cir. 2026) ("If it were ever an excuse to plead ignorance of the risks of using generative AI to draft a brief without verifying its output, it is certainly no longer so."); see also United States v. McGee, 806 F. Supp. 3d 1264, 1275 (S.D. Ala. 2025) ("Given the broad attention . . . to the problem with AI generated cases and authorities, no attorney can claim ignorance or simply bury their head in the sand when it comes to their own use of AI (regardless of what program they use).").

And yet here we are. Attorney Keefe used a generative AI tool from the beginning of this appeal without any apparent guardrails. Capital Standard's original initial brief was replete with nonexistent quotations and purported statements of law with wholly inaccurate cites. Soon after filing that initial brief, Capital Standard moved to file an amended initial brief because, Attorney Keefe claimed, he had identified "critical issues that require clarification and elaboration." Apparently, however, ensuring the accuracy of his purported authorities was not among those "critical issues" because Capital Standard's subsequent amended initial brief included at least thirty-one instances of Attorney Keefe's citing or quoting existing cases for propositions they do not contain. That amended initial brief contained numerous whoppers, including, to give just a few:

• Repeatedly citing Maciejewski v. Holland, 441 So. 2d 703 (Fla. 2d DCA 1983), a two-page opinion explaining why the complaint there stated a cause of action for declaratory relief, for unrelated propositions such as that "[u]nder Florida law, a party's actions that affirm the validity of a transaction preclude subsequent challenges to that

Only the 2026 cases referenced above postdate our January 8, 2026, order to show cause to Attorney Keefe.

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