Poison Quest Not working properly

So, i started the quest, talked to mariana, talked to the farmer and his friend found out that they did not eat at the tavern and that he wanted to make a move on her. But I had to leave so i quite the game upon coming back when i approach the farmer he asks me about whether i have done as he ask me to also I have already given him the potion but he keeps asking for me to bring him the potion. When i report to the bailiff to tell him the story the information I have found out from the fisherman does not come up and bailiff ask me to get more details. And now I can’t talk to the fisherman anymore either.

windows 8.1
Intel Core I7-4790
Nvidia Geforce GTX970
Ram 16GB

Have you used the save (by exit), and continue funktion? In the alpha its very buggie. Sometimes the quests are broken, after saving.

so how would you go about it? just start all over again?

If you want to complete the quest, yes. Alternatively, since the beta comes out tomorrow, just do it then.

This is the most recent walk through I did of this quest.