diff --git a/library/Icinga/Data/Db/DbQuery.php b/library/Icinga/Data/Db/DbQuery.php
index a89544be8..b701f3ac0 100644
--- a/library/Icinga/Data/Db/DbQuery.php
+++ b/library/Icinga/Data/Db/DbQuery.php
@@ -223,7 +223,7 @@ class DbQuery extends SimpleQuery
      */
     public function isTimestamp($field)
     {
-        return $this;
+        return false;
     }
 
     public function whereToSql($col, $sign, $expression)