Today all of the pages that we had excluded from the lists of pages suddenly appeared on the site. As they did not have parent pages, they all appeared on every page, wrapping around the menu, so every page just had a blanket of links running down it.
We went to the pages and the box that we had unchecked was suddenly checked. To fix it, we had to go back through every page and uncheck the box again. This occured even on pages that hadn't been touched in days.
What could have caused this? Is there a way to ensure it does not happen again?