cac:InvoiceLine/cac:Item/cac:CommodityClassification/cbc:ItemClassificationCode | cac:CreditNoteLine/cac:Item/cac:CommodityClassification/cbc:ItemClassificationCode[BR-65]-The Item classification identifier (BT-158) shall have a Scheme identifier.
Hitting this rule in production? Paste the invoice into the validator or wire the API into CI so it never ships broken again.