diff --git a/calendar/inc/class.calendar_so.inc.php b/calendar/inc/class.calendar_so.inc.php
index fb9fc494e6..d8a19748f1 100644
--- a/calendar/inc/class.calendar_so.inc.php
+++ b/calendar/inc/class.calendar_so.inc.php
@@ -1667,6 +1667,10 @@ ORDER BY cal_user_type, cal_usre_id
 					{
 						$event['recur_enddate'] = Api\DateTime::user2server($event['recur_enddate'], 'ts');
 					}
+					if (is_object($old_repeats['recur_enddate']))
+					{
+						$old_repeats['recur_enddate'] = Api\DateTime::user2server($old_repeats['recur_enddate'], 'ts');
+					}
 					// recurrences need to be truncated
 					if((int)$event['recur_enddate'] > 0 &&
 						((int)$old_repeats['recur_enddate'] == 0 || (int)$old_repeats['recur_enddate'] > (int)$event['recur_enddate'])