The openldap version that we use is 2.4.21. This issue consistently occurs when we export(slapcat) the content in ldif format and imported(slapadd) again into a clean ldap server.
I would note that 2.4.21 is 4.5 years old, and multitudes of bugs have been fixed since then. I strongly advise you to run a current release. In general, you're just wasting your time until you do.
--Quanah -- Quanah Gibson-Mount Server Architect Zimbra, Inc. -------------------- Zimbra :: the leader in open source messaging and collaboration