In Janson v. Katharyn B. Davis, LLC, 2015 WL 7253244, at *2 (C.A.8 (Mo.),2015), a renter lost a state court collection action, and then sued in federal court claiming that an affidavit filed filed in the state court action was false; namely, because it asserted that he owed rent.   How this side-stepped the Rooker-Feldman doctrine escapes me, but the 8th Circuit said it did:

Davis claims that the Rooker–Feldman doctrine deprives this court of jurisdiction because in the state court proceedings Janson had questioned Basler about the affidavit before judgment was entered. In Banks v. Slay, 789 F.3d 919, 922 (8th Cir.2015), our court pointed out the “proper focus” of the Rooker–Feldman doctrine has been explained by the Supreme Court: it is confined to the narrow ground of barring state court losers from inviting federal review of state court judgments. Exxon Mobil Corp. v. Saudi Basic Indus. Corp., 544 U.S. 280, 284 (2005). Janson alleges that an agent of Davis violated the FDCPA by swearing to an affidavit without knowing whether or not the information contained in the affidavit was true, but he does not allege that the information contained in the affidavit (that he owed rent) was false. Thus, his FDCPA suit is not directed at or attacking the state court judgment that he owed rent. Davis has not shown a lack of jurisdiction in this case.

So, the 8th Circuit instead relied on the lack of materiality, particularly in an underlying adversarial state court proceeding.

Even if we were to assume that Basler’s attestation were literally false, Janson has not plausibly alleged that he or anyone else was misled by that falsehood. In Hemmingsen v. Messerli & Kramer, P.A., 674 F.3d 814, 819 (8th Cir.2012), our court rejected a claim that a debt collector violated §§ 1692e and 1692f with its litigation activity, in part because no one there “was misled, deceived, or otherwise duped” by the contested court filings. Id . (quoting O’Rourke v. Palisades Acquisition XVI, LLC, 635 F.3d 938, 945 (7th Cir.2011) (Tinder, J., concurring)). The quoted concurring opinion in O’Rourke explains that courts link “false to misleading,” meaning “[i]f a statement would not mislead the unsophisticated consumer, it does not violate the FDCPA—even if it is false in some technical sense.” O’Rourke, 635 F.3d at 945. (Tinder, J., concurring) (internal quotation marks omitted).  Absent an allegation that he actually did not owe rent, Janson has not plausibly alleged that the defendant’s practice misled the state court in any meaningful way. Instead, Janson’s complaint indicates that a trial was had in which the state court received evidence before rendering a judgment on the underlying rent issue. We agree with the district court that on this record the defendant did not use “unfair or unconscionable means” prohibited by 15 U.S.C. § 1692f. Other circuit courts have applied a similar analysis. See, e.g., Gabriele v. Am. Home Mortg. Servicing, Inc., 503 F. App’x 89, 93–96 (2d Cir.2012) (concluding that plaintiff’s allegations about defendant’s court filings amounted to non misleading technical falsehoods which when made in the context of a state court adversary proceeding between two represented parties did not state plausible claims under §§ 1692e and 1692f of the FDCPA).