In my save, Wailon Lodge is stuck at three stars. The objective for four stars will not appear no matter what I try. All of my other museums are at five stars or above and I've gotten bronze or higher on all the challenge maps. I'm not sure what caused it. Someone else on Reddit posted having the same issue with two stars. Here's the thread I created:

https://old.reddit.com/r/TwoPointMuseum/comments/1j55364/walion_stuck_at_three_stars/?

My Two Point Museum folder is 92 MB compressed so I can't attach it to this ticket. If you want a subset of it, let me know what to extract. I uploaded the most recent log in case it helps in some way.

Edit - I just noticed that my map screen says two stars, but the museum itself shows three. I don't know if this helps or not.