Minion! Kill Them! Kills me

I’m level a 15 rogue, playing through Legion as assigned by Chromie. I am doing the quest “Minion! Kill Them!”, I have done this quest at least 20 times on various characters, never had a problem. This time, all of the quest creatures take virtually no damage from me and kill me with one or two hits. It’s like my level isn’t being scaled correctly. If I attack without Daglop the demon on my head, I can fight normally. To get him off temporarily I have to mount right before attacking.

04/20 Same issue at level 29 playing Demon Hunter. All of the mobs kill me in about 3 hits while I barely damage them. Very frustrating as I only have two quests left in the area and the other one has the same bug!