). Indeed, courts have invoked the doctrine of estoppel against government entities when not doing so would result in a "manifest injustice." 1555 Boston Rd. Corp. v. Fin. Adm'r of City of N.Y., 61 A.D.2d 187, 192 (2d Dep't 1978) (manifest injustice would result if city was not estopped by its actions w