At will serve breaks twisted appendages?

I got R3 Twisted appendages from this weeks chest, and it did a lot of damage. Recently changed my first talent to At will Serve to try it out and ran a +13 and noticed my damage was a lot lower. Looking at my damage done my appendages did next to nothing (500k total damage). Figured the talent was the only thing i changed so i went back to Infected claws and hit a dummy for 20-30 seconds, I procced 4 appendages (1.1m total damage). I know it’s kinda random, 1 appendage could do 250k total damage and for a 35-40 minute dungeon it only did 500k.