Pages not showing to add to menu

I have an older site with a large number of pages. I’m pulling pages into the primary menu, but many of the pages don’t appear.

If I search for the title they don’t show up and I can’t find them in the View All list.

If I go to the page I want to add, and change the title to a different name and save it, then it will come up in the search and I can add it. If I rename it to the original name it will disappear.

Is this a known issue? I haven’t been able to find anything about it. Is there a way to clear out or rebuild the pages for the menu?