Hi Mahesh,
Text join will use the language set on parameter LANGUAGE_SAP your DB connection. So I'm guessing your connection was set in another language. Check it with:
select * from m_session_context where connection_id = current_connection
If you generate a Planviz execution you'll be also able to see how's that being filtered (check for the basic plan operators on your T006T table.
Regards,
Lucas de Oliveira