I have multiple users who are no longer showing in the user list. One of the users I created an internal directory user to test, which associated that content to that user as the creator. I then changed the user name, and the LDAP user showed up in the list again, but was quickly disabled by Confluence. I then updated the Content table so that the LDAP user was the creator on those pages, and the user disappeared again.
I have tried re-indexing, which will list the users for a few minutes, but then they disappear. I have a feeling they are getting disabled in the DB for some reason. Either the content on the pages they are editing, or maybe a change from upper to lower case in LDAP on the user name, or ???