A party's prior appearances and execution of a stipulation in a New York court do not constitute a waiver of his subject matter jurisdiction defense, as a defect in subject matter jurisdiction may be raised at any time by any party or by the court itself, and subject matter jurisdiction cannot be created through waiver, estoppel, laches, or consent.
Matter of Hook v. Snyder, NY Slip Op 02458 (1st Dep't April 22, 2021)
