UBL-CR-568: A UBL invoice should not include the InvoiceLine Item Keyword

This warning rule checks that a UBL invoice or credit note does not include an item keyword (cbc:Keyword) inside the item (cac:Item) of any invoice line (cac:InvoiceLine) or credit note line (cac:CreditNoteLine). The test not((cac:InvoiceLine|cac:CreditNoteLine)/cac:Item/cbc:Keyword) passes only when no such cbc:Keyword is present; if any are found, the validator reports the warning. Since the severity is warning, the document is not rejected for this, but the validator recommends omitting the element.

Remove each cbc:Keyword element from cac:Item within cac:InvoiceLine (for an invoice) or cac:CreditNoteLine (for a credit note). In the producing system, do not map or generate an item keyword under line-level item information; leave the field empty or omit it.