Confluence shows the owner as Unknown User (username) in the content owner after removing the external user from the application.
Steps to Replicate
1. Add a user to the LDAP that can log into Confluence. Let's call it test1.
2. Log in as an admin, sync the LDAP directory on Confluence so the app is aware of the user, then Log Out as admin.
3. Log in as the new user (test1).
4. Click on "Add personal space" in the Create Space screen.
5. Copy the URL of the Space home page.
6. Log out as test1.
7. Remove the user from the LDAP/group.
8. Log in as admin and perform a directory sync, make sure the user does not exist any longer.
9. Access the space created by test1 user (the url we've copied).
The space/page should keep the name of the content owner, keeping their footprint.
We see Unknown User (test1) username as owner of the space.