Files without a valid group owner may be unintentionally inherited if a group is assigned the same Group Identifier (GID) as the GID of the files without a valid group owner.
Check
Verify all files and directories on the system have a valid group.
Check the owner of all files and directories with the following command:
Note: The value after -fstype must be replaced with the filesystem type. XFS is used as an example.
# find / -fstype xfs -nogroup
If any files on the system do not have an assigned group, this is a finding.
Fix
Either remove all files and directories from the system that do not have a valid group, or assign a valid group to all files and directories on the system with the "chgrp" command: