In Network-1 Techs., Inc. v. Hewlett-Packard Co., No. 2018-2338, 2020 WL 5666893 (Fed. Cir. Sept. 24, 2020), the Federal Circuit vacated and remanded the district court’s judgment as a matter of law on validity based on HP’s limited participation during a related IPR proceeding. The Federal Circuit explained that because a party joining an IPR cannot bring additional grounds for institution, the joining party cannot be estopped from raising other invalidity grounds in district court proceedings.