Some more info on the attributes that are causing the conflict:
$ sudo ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:/// -b cn=config olcDatabase={1}mdb olcDbIndex dn: olcDatabase={1}mdb,cn=config olcDbIndex: objectClass eq olcDbIndex: cn,uid eq olcDbIndex: uidNumber,gidNumber eq olcDbIndex: member,memberUid eq
Some more info on the attributes that are causing the conflict:
$ sudo ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:/// -b cn=config olcDatabase={1}mdb olcDbIndex {1}mdb, cn=config
dn: olcDatabase=
olcDbIndex: objectClass eq
olcDbIndex: cn,uid eq
olcDbIndex: uidNumber,gidNumber eq
olcDbIndex: member,memberUid eq