gistfile1.php

<?php
/*
 * Hack to restore the post_name that get_default_post_to_edit() noops
 * Our assigned post_name via wp_insert_post_data can get fubar on post-new.php
 *
 * @see https://core.trac.wordpress.org/browser/trunk/src/wp-admin/includes/post.php#L588
 */
add_filter( 'post_updated_messages', function( $messages ) {
	global $pagenow, $post;

	if ( 'post-new.php' == $pagenow && empty( $post->post_name ) ) {
		$post = get_post( $post->ID );
	}
	return $messages;
});