Adding invoice description to payment advice

In 12.1.3, when adding invoices description to EFT payment advice through IBY_FD_EXTRACT_EXT_PUB the solution works fine in all non-prod instance. However, the same pulls no descriptions and leaves it blank. Is there some sort of setup I need to check to ensure the is working? Not that non-prod instance are refresh from production.

  FUNCTION Get_Doc_Ext_Agg(p_document_payable_id IN NUMBER)

  RETURN XMLTYPE

  IS

    l_ins_doc_agg XMLTYPE;

  BEGIN

    --

    Select XMLConcat(XMLElement("Extend", XMLELEMENT("DocumentDescription", ai.description)))              

    INTO l_ins_doc_agg

    FROM iby_docs_payable_all dp,ap_invoices_all ai