fatalEN 16931syntax binding ruleCII
Only one DueDateTypeCode shall be present
An element that EN 16931 allows at most once appears more than once: Only one DueDateTypeCode shall be present
Keep the single correct occurrence and delete the rest. If you genuinely have several values, they belong in a repeatable group, not in repeated elements.
CII — context /rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeSettlement
count(//ram:ApplicableTradeTax/ram:DueDateTypeCode) = 0 or count(distinct-values(//ram:ApplicableTradeTax/ram:DueDateTypeCode)) = 1