diff --git a/include/class.orm.php b/include/class.orm.php
index 5a2d31f115728c22315191e0e7b33ebd4fc4c2b2..163e628b314908cb738f1d8b0f668eef69f00db6 100644
--- a/include/class.orm.php
+++ b/include/class.orm.php
@@ -1568,6 +1568,7 @@ class InstrumentedList extends ModelInstanceManager {
 
     function reset() {
         $this->cache = array();
+        unset($this->resource);
     }
 
     /**