XV-PL-04

The internal identifier … of Podmiot3 starts with a NIP that has no valid check digit; KSeF's production environment rejects the invoice (KSeF 2.0, weryfikacja faktury).

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

Context
fa:Podmiot3/fa:DaneIdentyfikacyjne/fa:IDWew
Test
pl:nip(substring(normalize-space(.), 1, 10))

Checked with KSeF FA(3)