Not especially. For as early as you can encounter Marcus in act 2 it's pretty high though. I usually save his fight for right before I head to grab Dame Aylin and have gotten a bit more powered up.
After more thought on the matter though I bet OP has karmic dice on. That option being on can make those crazy long bad and good luck streaks happen.
I turned karmic dice off all the way back in the mindflayer ship when that lvl.5 demon thing was when weaving my lvl.1 party and I thought the game was broke