Index: relationship_api.php
===================================================================
--- relationship_api.php	(revision 5171)
+++ relationship_api.php	(working copy)
@@ -581,7 +581,7 @@
 			$t_relationship_info_text .= $t_bug->summary;
 		}
 		else {
-			$t_relationship_info_text .= substr( $t_bug->summary, 0, $t_summary_wrap_at - 3 ) . '...';
+			$t_relationship_info_text .= mb_substr( $t_bug->summary, 0, $t_summary_wrap_at - 3, lang_get( 'charset', lang_get_current() ) ) . '...';
 		}
 
 		# add delete link if bug not read only and user has access level