diff --git a/core/model/DataObject.php b/core/model/DataObject.php
index 966de34f7..b6db294d2 100644
--- a/core/model/DataObject.php
+++ b/core/model/DataObject.php
@@ -702,7 +702,7 @@ class DataObject extends ViewableData implements DataObjectInterface,i18nEntityP
 
 			// Update the changed array with references to changed obj-fields
 			foreach($this->record as $k => $v) {
-				if(is_object($v) && $v->isChanged()) {
+				if(is_object($v) && method_exists($v, 'isChanged') && $v->isChanged()) {
 					$this->changed[$k] = true;
 				}
 			}
@@ -2970,4 +2970,4 @@ class DataObject extends ViewableData implements DataObjectInterface,i18nEntityP
 
 }
 
-?>
\ No newline at end of file
+?>