acf.php

/**
 * Include only published posts in post query.
 *
 * @param  array $args
 * @param  array $field
 * @param  int $post_id
 * @return array
 */
function nn_query_only_published_posts( $args, $field, $post_id ) {

    $args['post_status'] = array( 'publish' );

    return $args;
}
add_filter( 'acf/fields/relationship/query', 'nn_query_only_published_posts', 10, 3 );
add_filter( 'acf/fields/post_object/query', 'nn_query_only_published_posts', 10, 3 );
add_filter( 'acf/fields/page_link/query', 'nn_query_only_published_posts', 10, 3 );