Yeah I agree, someone saying they don't want to talk anymore because they've already written about something stops it being a discussion and makes it into some sort of lecture but without the notes. If you're insisting on telling someone you wrote about the current topic of conversation, you can just mention it and carry on with it. Like authors who go on podcasts, they'll say "Like I wrote in chapter X, I think that..." - the conversation shouldn't be killed off. Comes off as a bit arrogant.