Notwithstanding the jurisdictional nature of the time bar under § 315(b), the US Court of Appeals for the Federal Circuit determined that a party may waive a time bar argument if it failed to raise the issue with the Patent Trial and Appeal Board (PTAB) during the inter partes review (IPR) proceeding. Acoustic Tech. Inc. v. Itron Networked Solutions, Inc., Case No. 19-1061 (Fed. Cir. Feb. 13, 2020) (Reyna, J.).