BR-50
This id stands for 2 different rules, one per rule set below: Factur-X numbers its rules in each profile separately.
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.
A Payment account identifier (BT-84) shall be present if Credit transfer (BG-17) information is provided in the Invoice.
cac:PaymentMeans[cbc:PaymentMeansCode='30' or cbc:PaymentMeansCode='58']/cac:PayeeFinancialAccount
normalize-space(cbc:ID) != ''
Checked with EN 16931 Invoice (UBL), EN 16931 Credit Note (UBL), Croatia eRačun Invoice (UBL), Croatia eRačun Credit Note (UBL)
A Payment account identifier (BT-84) shall be present if Credit transfer (BG-16) information is provided in the Invoice.
//ram:SpecifiedTradeSettlementPaymentMeans[ram:TypeCode='30' or ram:TypeCode='58']/ram:PayeePartyCreditorFinancialAccount
normalize-space(ram:IBANID) != '' or normalize-space(ram:ProprietaryID) != ''
Checked with EN 16931 Invoice (CII)
A Payment account identifier (BT-84) shall be present if Credit transfer (BG-17) information is provided in the Invoice.
cac:PaymentMeans[cbc:PaymentMeansCode='30' or cbc:PaymentMeansCode='58']/cac:PayeeFinancialAccount
(cbc:ID) != ''
Checked with Romania RO e-Factura Invoice (UBL), Romania RO e-Factura Credit Note (UBL)