dbLocale is not always initialized

Steps :

• create a drupal civicrm (drupal 6 or 7)
• activate multilingual mode
• add a language
• run : drush provision-verify

Error :
Undefined offset: 1 backend.inc:163
Undefined variable: output backend.inc:170

After debugging, the problem happen because dbLocale is not defined in CRM_Core_DAO::query().
When i initialize the value, it's working fine. I don't why in this context dbLocale is not initialized but maybe we can force the initialization of dbLocale when we are in multilingual mode and the locale is empty ?