diff --git a/plugins/libcalendaring/libvcalendar.php b/plugins/libcalendaring/libvcalendar.php
index 938ccd07..65afde3c 100644
--- a/plugins/libcalendaring/libvcalendar.php
+++ b/plugins/libcalendaring/libvcalendar.php
@@ -997,7 +997,7 @@ class libvcalendar implements Iterator
 
         // set DTSTAMP according to RFC 5545, 3.8.7.2.
         $dtstamp = !empty($event['changed']) && !empty($this->method) ? $event['changed'] : new DateTime('now', new \DateTimeZone('UTC'));
-        $ve->add($this->datetime_prop($cal, 'DTSTAMP', $dtstamp, true));
+        $ve->DTSTAMP = $this->datetime_prop($cal, 'DTSTAMP', $dtstamp, true);
 
         // all-day events end the next day
         if ($event['allday'] && !empty($event['end'])) {
diff --git a/plugins/libcalendaring/tests/libvcalendar.php b/plugins/libcalendaring/tests/libvcalendar.php
index d8794acf..7fca464e 100644
--- a/plugins/libcalendaring/tests/libvcalendar.php
+++ b/plugins/libcalendaring/tests/libvcalendar.php
@@ -394,6 +394,7 @@ class libvcalendar_test extends PHPUnit_Framework_TestCase
         $this->assertContains('END:VTIMEZONE', $ics, "VTIMEZONE encapsulation END");
 
         $this->assertContains('BEGIN:VEVENT',       $ics, "VEVENT encapsulation BEGIN");
+        $this->assertSame(2, substr_count($ics, 'DTSTAMP'), "Duplicate DTSTAMP (T1148)");
         $this->assertContains('UID:ac6b0aee-2519-4e5c-9a25-48c57064c9f0', $ics, "Event UID");
         $this->assertContains('SEQUENCE:' . $event['sequence'],           $ics, "Export Sequence number");
         $this->assertContains('CLASS:CONFIDENTIAL',                       $ics, "Sensitivity => Class");