diff --git a/plugins/calendar/drivers/kolab/kolab_calendar.php b/plugins/calendar/drivers/kolab/kolab_calendar.php
index 7f660f32..107a764c 100644
--- a/plugins/calendar/drivers/kolab/kolab_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_calendar.php
@@ -670,22 +670,34 @@ class kolab_calendar extends kolab_storage_folder_api
 
     $i = 0;
     while ($next_event = $recurrence->next_instance()) {
-      $datestr = $next_event['start']->format('Ymd');
+      $datestr     = $next_event['start']->format('Ymd');
       $instance_id = $next_event['start']->format($recurrence_id_format);
 
       // use this event data for future recurring instances
       if ($futuredata[$datestr])
         $overlay_data = $futuredata[$datestr];
 
+      $rec_id      = $event['uid'] . '-' . $instance_id;
+      $exception   = $exdata[$datestr] ?: $overlay_data;
+      $event_start = $next_event['start'];
+      $event_end   = $next_event['end'];
+
+      // copy some event from exception to get proper start/end dates
+      if ($exception) {
+        $event_copy = $next_event;
+        kolab_driver::merge_exception_dates($event_copy, $exception);
+        $event_start = $event_copy['start'];
+        $event_end   = $event_copy['end'];
+      }
+
       // add to output if in range
-      $rec_id = $event['uid'] . '-' . $instance_id;
-      if (($next_event['start'] <= $end && $next_event['end'] >= $start) || ($event_id && $rec_id == $event_id)) {
+      if (($event_start <= $end && $event_end >= $start) || ($event_id && $rec_id == $event_id)) {
         $rec_event = $this->_to_driver_event($next_event, false, false);
         $rec_event['_instance'] = $instance_id;
         $rec_event['_count'] = $i + 1;
 
-        if ($overlay_data || $exdata[$datestr])  // copy data from exception
-          kolab_driver::merge_exception_data($rec_event, $exdata[$datestr] ?: $overlay_data);
+        if ($exception)  // copy data from exception
+          kolab_driver::merge_exception_data($rec_event, $exception);
 
         $rec_event['id'] = $rec_id;
         $rec_event['recurrence_id'] = $event['uid'];
diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index c2810ee9..ec60b509 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -1393,7 +1393,6 @@ class kolab_driver extends calendar_driver
     }
   }
 
-
   /**
    * Merge certain properties from the overlay event to the base event object
    *
@@ -1408,25 +1407,9 @@ class kolab_driver extends calendar_driver
     if (is_array($blacklist))
       $forbidden = array_merge($forbidden, $blacklist);
 
-    // compute date offset from the exception
-    if ($overlay['start'] instanceof DateTime && $overlay['recurrence_date'] instanceof DateTime) {
-      $date_offset = $overlay['recurrence_date']->diff($overlay['start']);
-    }
-
     foreach ($overlay as $prop => $value) {
       if ($prop == 'start' || $prop == 'end') {
-        if (is_object($event[$prop]) && $event[$prop] instanceof DateTime) {
-          // set date value if overlay is an exception of the current instance
-          if (substr($overlay['_instance'], 0, 8) == substr($event['_instance'], 0, 8)) {
-            $event[$prop]->setDate(intval($value->format('Y')), intval($value->format('n')), intval($value->format('j')));
-          }
-          // apply date offset
-          else if ($date_offset) {
-            $event[$prop]->add($date_offset);
-          }
-          // adjust time of the recurring event instance
-          $event[$prop]->setTime($value->format('G'), intval($value->format('i')), intval($value->format('s')));
-        }
+        // handled by merge_exception_dates() below
       }
       else if ($prop == 'thisandfuture' && $overlay['_instance'] == $event['_instance']) {
         $event[$prop] = $value;
@@ -1434,6 +1417,38 @@ class kolab_driver extends calendar_driver
       else if ($prop[0] != '_' && !in_array($prop, $forbidden))
         $event[$prop] = $value;
     }
+
+    self::merge_exception_dates($event, $overlay);
+  }
+
+  /**
+   * Merge start/end date from the overlay event to the base event object
+   *
+   * @param array The event object to be altered
+   * @param array The overlay event object to be merged over $event
+   */
+  public static function merge_exception_dates(&$event, $overlay)
+  {
+    // compute date offset from the exception
+    if ($overlay['start'] instanceof DateTime && $overlay['recurrence_date'] instanceof DateTime) {
+      $date_offset = $overlay['recurrence_date']->diff($overlay['start']);
+    }
+
+    foreach (array('start', 'end') as $prop) {
+      $value = $overlay[$prop];
+      if (is_object($event[$prop]) && $event[$prop] instanceof DateTime) {
+        // set date value if overlay is an exception of the current instance
+        if (substr($overlay['_instance'], 0, 8) == substr($event['_instance'], 0, 8)) {
+          $event[$prop]->setDate(intval($value->format('Y')), intval($value->format('n')), intval($value->format('j')));
+        }
+        // apply date offset
+        else if ($date_offset) {
+          $event[$prop]->add($date_offset);
+        }
+        // adjust time of the recurring event instance
+        $event[$prop]->setTime($value->format('G'), intval($value->format('i')), intval($value->format('s')));
+      }
+    }
   }
 
   /**