Test steps :-
1. configure unix sync source.
2. Add group "grp1"
3. check sync source of group 'grp1'. it will be Unix.
4. change sync source to LDAP, having "grp1" already present.
5. restart user sync service.
6. check sync source of group 'grp1'. it will be updated to "LDAP", Which is not the accepted behaviour.
Ideally grp1 should not be synced as it is already present.