Some users, who should be able to, can't find pages in the Confluence search if their visibility was restricted by the Issue Publisher.
This only happens if the page restrictions set by the Issue Publisher include a group with at least one upper case letter in the name and only to users who can exclusively see the page because of their membership in this group.
Users that are added directly to the restrictions are not affected. Users that are members of restricted groups that don't contain any upper case letters are also not affected.
The ability to access the page (e.g. via a link) is also not affected for any user.
This is a problem in the REST API of Confluence.
As a workaround you should only use groups without upper case letters in their name.
For individual pages you can also manually open the restrictions of a page and click 'Apply' without any changes, as this fixes the problem as well.