revised.php

add_action( 'pre_get_posts', 'tribe_post_date_ordering', 51 );

function tribe_post_date_ordering( $query ) {
	if ( ! empty( $query->tribe_is_multi_posttype ) ) {
		remove_filter( 'posts_fields', array( 'Tribe__Events__Query', 'multi_type_posts_fields' ) );
		$query->set( 'order', 'DESC' );
	}
}