I am playing Assassin's Creed: Valhalla on the PS4. I was working on the River Raid quests and got to River Rhime to take on the quest "The Ulfberht Sword." For this quest, you have to defeat two captains before the champion appears. I went to Fort Ehrenfels and defeated one captain with no issue. I confirmed the kill, and the quest updated accordingly to say that I had killed 1/2 captains. I raided a few more locations and then left the river. After doing some more raids on other rivers to reduce the river defenses, I came back to River Rhime. This time, I went to Katzenelnbogen to kill the second captain. I defeated him and confirmed the kill. However, the mission did not update. It still says that I had only killed 1/2 captains. The mission markers do not update, and the next mission objective does not appear. By all appearances, I am no longer able to continue this mission and complete it. I have tried reloading the game to before I went on the raid and trying this again, but I get the same results.