For this quest you need to talk to a deserter agitator and then kill them. For the bug what you do is talk with the agitator and then click the chat option. After that run and get something in between you and them. They will run the opposite way and then despawn while you get the credit of killing them. If that didnt make sense heres pictures
Im not sure if this will work with every quest were you need to talk to someone and kill them but if i get another like that ill try it.
If you get the quest credit right away you know you did it right.
Also, make sure you have a big enough object.
My bar addon is a tweaked version of photek ui.