Scratching my head on this for a while, didnt really affect much so never dug deep.
If you have duplicate entries in your /etc/groups or duplicates in general, in our case the same group in /etc/group that was also in ldap. So essentially
returns duplicates with different ids. The first entry will take precedence when running chown and other unix utils. Therefore you will get files with a different gid than you would expect.