/ubl:Invoice/cac:AllowanceCharge[cbc:ChargeIndicator = false()] | /cn:CreditNote/cac:AllowanceCharge[cbc:ChargeIndicator = false()][BR-CO-05]-Document level allowance reason code (BT-98) and Document level allowance reason (BT-97) shall indicate the same type of allowance.
Hitting this rule in production? Paste the invoice into the validator or wire the API into CI so it never ships broken again.