I'm having the same issue after placing one-way archways throughout my exhibit. Because people are trying to enter through my exit point it is stating that all of my exhibits are unreachable to some people, but if they just entered through the entrance point then it wouldn't be an issue.

I get this too. Nothing seemed to have triggered it, I didn’t get an exclamation warning about an unreachable exhibit but I notice the visitors are t moving, even when I move the exhibit.they stand still.

one drive link as follows https://drive.google.com/file/d/1b9rIDhu6N4tJ5APDXTV4Yex5BSPmSzXn/view?usp=drivesdk

I've just had the same thing after resizing an aquarium.  There were about 10 guests who were inside the resized exhibit.  They got kicked out and then all the alert boxes started appearing.

Hello! I have encountered the same bug. I was renovating one of the buildings in my museum and moving around exhibits when I started receiving notifications of unreachable exhibits. This involves all exhibits I have in the museum including those in a separate building that haven’t been touched yet. I’ve tried removing some decorations and objects near the exhibits but it still notifies as unreachable. All pathways and doors/arches are also free from any obstruction.

Exactly the same thing.

Yes, I know this is a design decision, not a bug. I disagree that it makes the game more fun in any way. I know if Two Point wanted, they could put up a "stuck" icon just like a "thirsty" or "bored" icon over a guest -- the fact that they choose not to reinforces that it's a design decision, and that it's working as intended. "Guess where the mystery hidden guest is or you can't play the game" is not fun, it's not entertaining, it's not challenging -- it's just frustrating, and I can get plenty of that IRL. "An exhibit seems to be unreachable for a few people" for every single exhibit, with only a few seconds after closing all of those popups to try to find the cause before it starts again -- pausing the game doesn't help, because I have to see how guests do (or don't) move -- is absolutely. not. fun.  Not in any way.

TwoPoint, when you intentionally present players with a problem (all those popups preventing gameplay) with no way to solve it, you are making your game less fun, not more. You are making players less willing to buy your future games, not more. At least give us a chance!