Rootdredge bug

Good afternoon,

While progressing through the Act 3 cruel difficulty, I have defeated the stage unique Rootdredge, but the token on the act map fails to signify that I have defeated him. I have reset the map and killed him again and the act map doesn't show that I have defeated him. I shut down the game and started it back up the next day and killed rootdredge again, but it still doesn't signify that I killed him on the act map.

Thank you!