[-] BO : added important check of the default language for ObjectModel multilang properties

classes/ObjectModel.php

@@ -859,6 +859,8 @@ abstract class ObjectModelCore
 			$values = $this->$field;
 			if (!is_array($values))
 				$values = array($this->id_lang => $values);
+			if (!isset($values[Configuration::get('PS_LANG_DEFAULT')]))
+				$values[Configuration::get('PS_LANG_DEFAULT')] = '';
 
 			foreach ($values as $id_lang => $value)
 			{