Potion Making Quest Bugged

I was playing with my friend in a party and I did this quest. It asked for eight red mushrooms, and then I went into the boss room. It told me I need to get his chest plate and bring it to him, but, my friend picked it up and it is a untradable item so he can not give it to me and I am unable to fight the boss again. So I need a fix for this because otherwise I will never be able to finish this quest. EDIT: Changing servers will not help this situation.

 

I tried to complete this quest on my other character today, and it didn't let me, the boss didn't spawn at all... You might need to wait.
Radical solution - /fixquests, but you'll need this command for further quests, so its up to you

 

Please don't post multiple threads about the same issue.
As you already created another thread please use that one.
/closed