fatalEN 16931syntax binding ruleCII
Only one TaxPointDate shall be present
More than one VAT point date (BT-7) is present on the invoice. EN 16931 gives this a single value, so a receiver has no rule for choosing between the copies and must reject the document.
Keep the one VAT point date (BT-7) that is correct and delete the others. Repeated singular elements almost always come from a serialiser emitting every value it holds instead of choosing one — fix it at the source, not by trimming the output file.
CII — context /rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeSettlement
count(ram:ApplicableTradeTax/ram:TaxPointDate) <= 1
Nothing is stored, and the whole invoice is checked, not just this rule. A PDF only works if it is Factur-X / ZUGFeRD — a PDF with the invoice XML inside it.