Help Quest Is Broken

hello there, I have been doing some questing recently with a friend of mine. My ign is Mattman_k924. We did the potions master quest but it broke... for me. When we defeated the guy in the house next to The Assistant, I crashed. When I got back on, my friend took both of the chest plates we were supposed to give to the assistant to finish the quest. The chest plate is untradeable so we couldn't trade it. I tried waiting for the dude to respawn but he didn't. I logged in and out of the server and worlds and he didn't respawn. But then I got the idea to just talk to the assistant. I did and he didn't congratulate me or anything. He just said "find me 8 red mushrooms to make the potion weaker." This is what he said before we went to fight the boss-like dude. I found the 8 and he kept saying what he said before, "bring me 8 red mushrooms blah blah blah" and now I can't complete the quest. Please try to fix this.

 

Try going back into the house with the guy in it, he should respawn once you exit and re-enter the house. And you don't need to collect more mushrooms, that message showing up again is likely a bug. You will be able to kill him again and get his drop.