diff --git a/core/attributedef.class.inc.php b/core/attributedef.class.inc.php
index f1e47dd65..ef62d87b0 100644
--- a/core/attributedef.class.inc.php
+++ b/core/attributedef.class.inc.php
@@ -1135,8 +1135,18 @@ class AttributeLinkedSet extends AttributeDefinition
 			return false;
 		}
 
-		// Both values are Object sets
-		return $val1->HasSameContents($val2);
+		// Note: maintain this algorithm so as to make sure it is strictly equivalent to the one used within DBObject::DBWriteLinks()
+		$sExtKeyToMe = $this->GetExtKeyToMe();
+		$sAdditionalKey = null;
+		if ($this->IsIndirect() && !$this->DuplicatesAllowed())
+		{
+			$sAdditionalKey = $this->GetExtKeyToRemote();
+		}
+		$oComparator = new DBObjectSetComparator($val1, $val2, array($sExtKeyToMe), $sAdditionalKey);
+		$aChanges = $oComparator->GetDifferences();
+
+		$bAreEquivalent = (count($aChanges['added']) == 0) && (count($aChanges['removed']) == 0) && (count($aChanges['modified']) == 0);
+		return $bAreEquivalent;
 	}
 
 	/**
diff --git a/core/dbobject.class.php b/core/dbobject.class.php
index b4889da34..24fc4bc1e 100644
--- a/core/dbobject.class.php
+++ b/core/dbobject.class.php
@@ -1366,9 +1366,10 @@ abstract class DBObject implements iDisplay
 			if (!array_key_exists($sAttCode, $this->m_aTouchedAtt)) continue;
 			if (array_key_exists($sAttCode, $this->m_aModifiedAtt) && ($this->m_aModifiedAtt[$sAttCode] == false)) continue;
 				
+			// Note: any change to this algorithm must be reproduced into the implementation of AttributeLinkSet::Equals()
 			$sExtKeyToMe = $oAttDef->GetExtKeyToMe();
 			$sAdditionalKey = null;
-			if ($oAttDef->IsIndirect())
+			if ($oAttDef->IsIndirect() && !$oAttDef->DuplicatesAllowed())
 			{
 				$sAdditionalKey = $oAttDef->GetExtKeyToRemote();
 			}