syncrepl schema error

Hi Team,

We have configured master slave openldap replication in our environment. Default NIS schema was modified for the attribute memberUid to be case insensitive. During replication after some of the records are transferred we are seeing below error.

Nov 17 08:06:57 abc.com slapd[2356]: syncrepl_message_to_entry: rid=003 mods check (memberUid: value #30 provided more than once) Nov 17 08:06:57 abc.com slapd[2356]: do_syncrepl: rid=003 rc 20 retrying

If remove the schema changes replication works fine. Could you please let us know whats going wrong with the configuration?

Thanks in advace

Regards, Aravind M D