F-LIB336

PaymentMeansCode = 93, InstructionID must be a numeric value when PaymentID equals 71 or 75.

error: the document is invalid

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.

Test
(cbc:PaymentMeansCode = '93') and ((cbc:PaymentID = '71' or cbc:PaymentID = '75') and (not(exists(cbc:InstructionID)) or (matches(cbc:InstructionID, '[^\d]+'[.]))) or (cbc:InstructionID = ''))

Checked with Denmark OIOUBL 2.1 Invoice