The Federal Circuit has overturned a noninfringement verdict for HP and HP Enterprise (HPE) against Network-1 Technologies, Inc., ruling on September 24 that a Texas jury’s finding on that issue depended on an erroneous claim construction and remanding for further proceedings. However, the appeals court also reversed and remanded a ruling by District Judge Robert W. Schroeder III that the defendants were estopped from challenging the validity of the asserted Power-over-Ethernet (PoE) patent due to the defendant’s joinder to another company’s inter partes review (IPR), a decision that had resulted in the reversal of that same jury’s finding that the patent was invalid. Rather, the Federal Circuit ruled that HP and HPE could not “reasonably . . . have raised” their district court invalidity arguments—which were different than the grounds raised in the IPR—under its recent decision in Facebook v. Windy City Innovations, which in part bars the joinder of new issues to an already instituted IPR.