ldapsearch weird output sorting

[nublaii]

I am using a backup script that queries the ldap server for email and server of each user.

This is what I run

ldapsearch -x -H ldap://mail.example.com:389 -D uid=zimbra,cn=admins,cn=zimbra -w password -LLL "(objectclass=zimbraAccount)" zimbraMailDeliveryAddress zimbraMailHost | grep -A1 -B1 -e user1 -e user2 -e user3

I assumed the output would be sorted following the query order: first the key 'zimbraMailDeliveryAddress', then 'zimbraMailHost'.

Out of around 700 users, I get 690 answers following that rule, but I get 10 or so that are inverted, like this

dn: uid=user1,ou=people,dc=example,dc=com
zimbraMailDeliveryAddress: user1@example.com
zimbraMailHost: mail.example.com

--

dn: uid=user2,ou=people,dc=example,dc=com
zimbraMailHost: mail.example.com                 <------
zimbraMailDeliveryAddress: user2@example.com     <------

--

dn: uid=user3,ou=people,dc=example,dc=com
zimbraMailDeliveryAddress: user3@example.com
zimbraMailHost: mail.example.com

Is this a expected behaviour? The -S flag to sort output doesn't work on the key-value pair order...