Fixture ID: allowanceRated_AE · XPath: /ubl:Invoice/cac:AllowanceCharge[2]/cac:TaxCategory/cbc:Percent
The document level charge at charges[0] uses VAT category AE (Reverse charge), so its VAT rate (BT-103) must be 0 (zero), but it is 19. The seller charges no VAT at all on a reverse-charge document — the buyer does. A rate here would be you quoting a percentage for tax you are not accounting for, and the buyer's own rate may differ from yours anyway, since the applicable rate is the one in their member state.
BR-AE-07Set charges[0].vatRate to 0, or omit it — this library normalises the rate for category AE either way. If you did mean to charge 19% VAT on this charge, the category should be S instead, and that will change which breakdown group it nets into.
"vatCategory": "AE", "vatRate": 0