I PMed you last night (early this morning) with my case.
I ran through the mini-arc to stop Nemisis from forming a non-agression pact with CoT. I was the team leader and the mission owner. At the end of the mini-arc, my teammate scored the final hit to defeat that last mob. We both got the mission complete message, but only she got the Corruptor badge. I called the conact back and he said "Good job, no badge"
Also, it's worth mentioning that she was given the mission XP/inf bonus and I was not.
I just want to mention this in the public forum so that everyone can know there'a potential bug with this mission, and we can all get confirmation when it's found/fixed.
Danke.