tribe-admin-events-list.class.php

<?php

/**
 * update ~line 26 to include 2 argument params as such:
 */
add_filter( 'posts_orderby',  array( __CLASS__, 'events_search_orderby' ), 10, 2 );

/**
 * update static function `events_search_orderby` (replace with the following method starting at ~line 159)
 */
public static function events_search_orderby( $orderby_sql, $query ) {
	if ( get_query_var('post_type') != TribeEvents::POSTTYPE ) {
		return $orderby_sql;
	}

	global $wpdb;
	$sort_column = ( $query->is_main_query() ) ? $wpdb->postmeta : 'eventStart';

	$endDateSQL = " IFNULL(DATE_ADD(CAST($sort_column.meta_value AS DATETIME), INTERVAL eventDuration.meta_value SECOND), eventEnd.meta_value) ";
	$order = get_query_var('order') ? get_query_var('order') : 'asc';
	$orderby = get_query_var('orderby') ? get_query_var('orderby') : 'start-date';

	if ($orderby == 'start-date') {
		$orderby_sql = " {$sort_column}.meta_value {$order}, {$endDateSQL} {$order}";
	} else if ($orderby == 'end-date') {
		$orderby_sql = "{$endDateSQL} {$order}, {$sort_column}.meta_value {$order}";
	}

	return $orderby_sql;
}