diff --git a/calendar/inc/class.calendar_boupdate.inc.php b/calendar/inc/class.calendar_boupdate.inc.php
index 9b53bbfe5f..5c6083a044 100644
--- a/calendar/inc/class.calendar_boupdate.inc.php
+++ b/calendar/inc/class.calendar_boupdate.inc.php
@@ -187,7 +187,7 @@ class calendar_boupdate extends calendar_bo
 				{
 					if ($overlap['participants'][$uid][0] == 'R')
 					{
-						unset($common_parts[$uid]);
+						unset($common_parts[$n]);
 						continue;
 					}
 					if (is_numeric($uid) || !in_array($uid[0],$types_with_quantity))
@@ -1793,4 +1793,4 @@ class calendar_boupdate extends calendar_bo
 			'master_event' => $master_event,
 		);
     }
-}
\ No newline at end of file
+}