If you visit the mansion on April Fool's day it triggered a dialogue with Shuu even though I had never met him before this point at all. Not sure why this happened?
I'm not surprised. The game has a lot of continuity issues. They're not annoying enough to break game enjoyment, but they do make things feel out of place, haha. I hope you're still enjoying the game despite this issue! I also hope the game dev will resolve it. I believe they're busy with their other projects though, so I doubt it'd be anytime soon. Oh well, let's hope for the best!