In Behrens v. JPMorgan Chase Bank N.A., — F.4th —, 2024 WL 1080026 (2d Cir. Mar. 13, 2024), the U.S. Court of Appeals for the Second Circuit addressed a question of first impression in the circuit: whether a district court is required to exercise subject-matter jurisdiction where it exists, even if it is invoked belatedly.