BR-S-10: An exemption reason on a standard-rated transaction
This code shows up when an electronic invoice is validated. Here is what it means, why it fires, and what to change in the file.
Why this code appears
A standard-rated breakdown (category S) carries an exemption reason (BT-120) or reason code (BT-121). VAT at the standard rate has nothing to justify: the presence of that reason almost always signals a template copied from an exempt invoice.
How to fix it
Remove ExemptionReason and ExemptionReasonCode from category S breakdowns. Keep them only on the categories that require one: E, AE, K, G, O.
Where it happens
This code comes from EN 16931, the European e-invoicing standard. It concerns business term BT-120.