So, I think I've encountered a bug in the quest "Regrowing a Tongue". After reading Adrosu Balmayn's note, the journal tells me to retrieve a tongue-regrowing potion from Teris Andrethi. But when I approach Teris he is instantly hostile, and after being forced to kill him I find he doesn't have the potion in his inventory. I'm assuming I'm supposed to be able to negotiate with him for the potion rather than kill him?