//cac:InvoiceLine/cac:AllowanceCharge[cbc:ChargeIndicator = false()] | //cac:CreditNoteLine/cac:AllowanceCharge[cbc:ChargeIndicator = false()][BR-42]-Each Invoice line allowance (BG-27) shall have an Invoice line allowance reason (BT-139) or an Invoice line allowance reason code (BT-140).
Hitting this rule in production? Paste the invoice into the validator or wire the API into CI so it never ships broken again.