When renaming a group in Notes, the wrong name is written in the AdminP request document.
Define a person X as the admin/owner of a group. The group name then appears on the person document in Notes in the "Administration" section.
Now you rename the group, let all processes go through and then look for the AdminP document including the response log "Rename Group in Person Documents". If one exists and it is confirmed that this part has been executed, you can still see the old group name on the above person document.
The old group name is no longer visible on the person document (and basically globally in the Notes environment). The renaming of the references also took place.
The group was only renamed in the address book. The references are still available with the old names.