I can't recall who triggered it. I lost 2 towns folk getting to that point of the mission.
The night I received the part I put it in storage as it was past business hours. Took it back out in the morning to try to proceed. I've spoken with every shop owner and all 10 towns folk. Tried dropping it on them before during and after their normal conversation, I only get message 'you cannot drop that'. One of my towns folk has had odd conversation since I got that piece. With first mayor he began to have no daily requests, would give me a 'token of friendship' then randomly follow me around wanting to talk then having a random conversation. A couple days ago my 2nd mayor took over and that towns person will now ask for his daily item, it won't 'save' to the to do list or as a request when speaking with him and no thought bubble. I'm guessing he was my target person and since it got stored it messed up the pattern maybe.
*edit* I suppose this is maybe best in tech section now, sorry bout that

Oh and new development today. The odd villager is letting me get unlimited gifts from him.