Newbie player here. In the first act of the game I had 3 different uruks that kept coming back for more, no matter how many times I killed them. The first was a guy I chopped up and turned into more machine than uruk. The second was a guy I killed with flies and he became some twisted, fly infested monstrosity. The third guy I killed with fire and he came back with his body scorched all to hell. It was freaking awesome.

Now, 25 - 30 hours later I'm in act 3, and I havent seen any of those guys since act 1. All of those guys disappeared and I haven't had any more nemesis uruks. Captains just die and never seem to come back anymore. Is my game bugged?