As reported on the Pocket Camp Reddit, since the last update, opening Phoebe’s fortune cookie is causing players’ games to crash and not reopen unless they completely uninstall and reinstall. This is currently only available via certain gifts and the Furniture and Cookie plan and is not an active or reissued cookie, but you could encounter it from a gift or it may possibly already be in your inventory uneaten. A commenter in the thread said Nintendo tech support was aware of the issue