XV-AT-02
The beneficiary account has no IBAN; e-Rechnung.gv.at takes bank transfer details as an IBAN only (BankAccountNr and BankCode are not enough).
What the rule checks
As the rule set's publisher wrote it. The rule runs on every element the context matches, and fails where the test is false; the validator reports the line of that element.
/*:Invoice/*:PaymentMethod/*:UniversalBankTransaction/*:BeneficiaryAccount
normalize-space(*:IBAN) != ''
Checked with Austria e-Rechnung.gv.at (ebInterface 6.1), Austria e-Rechnung.gv.at (ebInterface 6.0)