Documents, generated by billing during the Daily Billing process (Billing and Renewal Orders) have details that are not localized into account's language.
By default, Billing and Renewal Orders that are automatically generated by the billing, use the default locale. Also, a situation is possible where one Billing Order contains localized and not localized lines: such situation can happen if an account has customer class with the "Per Account" billing type and different types of orders are included into one invoice.
It is possible to force the billing to generate Billing and Renewal orders using an account's locale. This action requires the database update and therefore is recommended to be done by the Odin Technical Support. Note that service 'pba' should be restarted to apply the changes.