Captain’s need - Kill pirates

Im lv 30 and im doing main quest Captain’s need where i have to kill 9 pirates in Westmarch pub. I killed 7 so i have 7/9 but there aren’t other 2 pirates. There are 3 lagged pirates but only I can see them and I cant hit them so they cant be killed. Can i somehow restart this quest? Or what should i do i can’t move on to other quest so i’m stuck.

Thanks for all advices