Simply ignore "custom_permalink" postmeta for revision

add_filter("owf_unset_postmeta", "owf_unset_custom_permalink_meta", 20, 1);
function owf_unset_custom_permalink_meta( $post_metas ) {
	// set custom permalink meta from the post_metas
	$post_metas[] = 'custom_permalink';
	return $post_metas;
}