diff --git a/plugins/libkolab/lib/kolab_format.php b/plugins/libkolab/lib/kolab_format.php
index 0f19e1a9..c72f9ac3 100644
--- a/plugins/libkolab/lib/kolab_format.php
+++ b/plugins/libkolab/lib/kolab_format.php
@@ -61,8 +61,11 @@ abstract class kolab_format
         if (!$tz) $tz = self::$timezone;
         $result = new cDateTime();
 
-        if (is_numeric($datetime))
-            $datetime = new DateTime('@'.$datetime, $tz);
+        // got a unix timestamp (in UTC)
+        if (is_numeric($datetime)) {
+            $datetime = new DateTime('@'.$datetime, new DateTimeZone('UTC'));
+            if ($tz) $datetime->setTimezone($tz);
+        }
         else if (is_string($datetime) && strlen($datetime))
             $datetime = new DateTime($datetime, $tz);
 
@@ -71,6 +74,7 @@ abstract class kolab_format
 
             if (!$dateonly)
                 $result->setTime($datetime->format('G'), $datetime->format('i'), $datetime->format('s'));
+
             if ($tz)
                 $result->setTimezone($tz->getName());
         }
diff --git a/plugins/libkolab/lib/kolab_format_contact.php b/plugins/libkolab/lib/kolab_format_contact.php
index eb09d64a..02e3e899 100644
--- a/plugins/libkolab/lib/kolab_format_contact.php
+++ b/plugins/libkolab/lib/kolab_format_contact.php
@@ -274,6 +274,7 @@ class kolab_format_contact extends kolab_format
 
 
         // cache this data
+        unset($object['_formatobj']);
         $this->data = $object;
     }
 
diff --git a/plugins/libkolab/lib/kolab_format_distributionlist.php b/plugins/libkolab/lib/kolab_format_distributionlist.php
index 9fe28c19..3c5047c3 100644
--- a/plugins/libkolab/lib/kolab_format_distributionlist.php
+++ b/plugins/libkolab/lib/kolab_format_distributionlist.php
@@ -77,6 +77,10 @@ class kolab_format_distributionlist extends kolab_format
         }
 
         $this->obj->setMembers($members);
+
+        // cache this data
+        unset($object['_formatobj']);
+        $this->data = $object;
     }
 
     public function is_valid()