@Satsuma to clarify I helped Sazza after killing every single NPC in the goblin camp and then left the area and took a long rest
After freeing Sazza and she tells you to meet her near the camp. when you meet her and talk to her and she says she'll help you into the camp and put in a good word for you for the guards, only for her character model to vanish after she says this
She appears next to where Minthara is supposed to be but even though I knocked out Minthara her body was gone. When I then walked to the area the cutscene between Sazza and Minthara occurs, meaning Minthara's character teleported over. Since I looted her body she was now in her underwear during the cutscene. And then I told Minthara I was going to kill her and triggered combat, only for Sazza's and Minthara's bodies to immediately vanish and then the Sazza quest completed