I think I made a mistake of alt-tabbing to checkvist and hitting space when an item was selected (not sure how else this could have happened). Now everything below it is marked as completed, and it has a ton of nested items which were previously a mix of completed and to-do. If I mark the top level item as not completed, this makes everything below it incomplete too and marking tons of things as completed again would be extremely tedious.
I’m glad to see that I have daily backups. Is there a way I can restore the state from one of them? Or is there another way to fix this mess?