Custom QP

I have a custom query set up for a website that’s ordering the posts by the 2nd word of the post title (they are names, so it’s ordering by last names). My custom query is working perfectly in wordpress 3.7, but in 3.8 it does absolutely nothing. This is the code I wrote:

function custom_get_posts($query) {

	if (is_category()) {

		global $wpdb;
		global $post;

		if(is_category(14)) {

			$querystr = "
			SELECT DISTINCT wposts.ID
			FROM $wpdb->posts wposts
				LEFT JOIN $wpdb->postmeta wpostmeta ON wposts.ID = wpostmeta.post_id
				LEFT JOIN $wpdb->term_relationships ON (wposts.ID = $wpdb->term_relationships.object_id)
				LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
			WHERE $wpdb->term_taxonomy.term_id IN ('14')
				AND wposts.post_status='publish'
			ORDER BY SUBSTR(LTRIM(wposts.post_title), LOCATE(' ', LTRIM(wposts.post_title))) ASC
			";

			$pageposts = $wpdb->get_results($querystr, OBJECT);

			$pageposts_arr = array();
			foreach ($pageposts as $pagepost) {
				array_push($pageposts_arr, $pagepost->ID);
			}

			if($query->is_main_query()) {
				$query->query_vars['post__in'] = $pageposts_arr;
				$query->query_vars['orderby'] = 'post__in';
			}

		} elseif (is_category(24)) {
			if($query->is_main_query()) {
				$query->query_vars['orderby'] = 'modified';
			}
		}

	}

	return $query;
}
add_filter('pre_get_posts', 'custom_get_posts');