Index: src/wp-admin/includes/post.php
===================================================================
--- src/wp-admin/includes/post.php	(revision 29719)
+++ src/wp-admin/includes/post.php	(working copy)
@@ -1207,7 +1207,7 @@
 	} else {
 		if ( function_exists( 'mb_strlen' ) && mb_strlen( $post_name ) > 30 ) {
 			$post_name_abridged = mb_substr( $post_name, 0, 14 ) . '…' . mb_substr( $post_name, -14 );
-		} elseif ( strlen( $post_name ) > 30 ) {
+		} elseif ( ! seems_utf8( $post_name ) && strlen( $post_name ) > 30 ) {
 			$post_name_abridged = substr( $post_name, 0, 14 ) . '…' . substr( $post_name, -14 );
 		} else {
 			$post_name_abridged = $post_name;