I had a similar problem a while back after adding a new server - the LDAP replica just wouldn't replicate. I found that if I did a kill -HUP to the slapd process, then it seems to force it to sync. Give that a shot also.. BTW, the "firstname.lastname@example.org" is an example account that wasn't syncing from the master server.
zimbra@devzimbra:~$ ps ax | grep slap
6329 ? Ssl 0:00 /opt/zimbra/openldap/libexec/slapd -l LOCAL0 -4 -u zimbra -h ldap://devzimbra.domain.com:389 -f /opt/zimbra/conf/slapd.conf
zimbra@devzimbra:~$ kill -HUP 6329
zimbra@devzimbra:~$ zmprov gaa | grep dev