BuddyPress.org

I have listed my members alphabetically by their last name adding this to functions.php in my child theme:

function alphabetize_by_last_name( $bp_user_query ) {
    if ( 'alphabetical' == $bp_user_query->query_vars['type'] )
        $bp_user_query->uid_clauses['orderby'] = "ORDER BY substring_index(u.display_name, ' ', -1)";
}
add_action ( 'bp_pre_user_query', 'alphabetize_by_last_name' );

And this in members-loop.php

<?php if ( bp_has_members( bp_ajax_querystring( 'members' ).'&type=alphabetical' ).'&exclude=1,4,3,5,512 ' ) : ?>

However some members have their middle names in the same field as their first name and somehow they are being listed in order of the middle name.