diff --git a/org.adempiere.base/src/org/compiere/model/ModelValidationEngine.java b/org.adempiere.base/src/org/compiere/model/ModelValidationEngine.java
index a092a71cd6..8c22fb0bcd 100644
--- a/org.adempiere.base/src/org/compiere/model/ModelValidationEngine.java
+++ b/org.adempiere.base/src/org/compiere/model/ModelValidationEngine.java
@@ -621,7 +621,7 @@ public class ModelValidationEngine
 			return;
 		//
 		String propertyName =
-			m_globalValidators.contains(listener)
+			(listener instanceof ModelValidator && m_globalValidators.contains((ModelValidator)listener))
 				? tableName + "*"
 				: tableName + listener.getAD_Client_ID();
 		ArrayList<FactsValidator> list = m_factsValidateListeners.get(propertyName);
@@ -666,7 +666,7 @@ public class ModelValidationEngine
 		if (tableName == null || listener == null)
 			return;
 		String propertyName =
-			m_globalValidators.contains(listener)
+			(listener instanceof ModelValidator && m_globalValidators.contains((ModelValidator)listener))
 				? tableName + "*"
 				: tableName + listener.getAD_Client_ID();
 		ArrayList<FactsValidator> list = m_factsValidateListeners.get(propertyName);
@@ -733,7 +733,7 @@ public class ModelValidationEngine
 			{
 				validator = list.get(i);
 				if (validator.getAD_Client_ID() == po.getAD_Client_ID()
-						|| m_globalValidators.contains(validator))
+						|| (validator instanceof ModelValidator && m_globalValidators.contains((ModelValidator)validator)))
 				{
 					String error = validator.factsValidate(schema, facts, po);
 					if (error != null && error.length() > 0)