fatalEN 16931syntax binding ruleUBL
Value tax point date shall occur maximum once
'Value tax point date' appears more than once, and this profile allows it at most once.
Keep the single correct 'Value tax point date' and delete the rest. Repeating an element that the semantic model treats as singular is usually a serialiser writing every value it has instead of choosing one.
UBL — context /ubl:Invoice | /cn:CreditNote
(count(cac:InvoicePeriod/cbc:DescriptionCode) <=1)