CRP20215

El campo TipoCambioP debe contener el valor "1".

In English A payment in MXN must have TipoCambioP 1.

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
pago20:Pagos/pago20:Pago
Test
not($cur = 'MXN') or (@TipoCambioP and mx:dec(@TipoCambioP) = 1)

Checked with CFDI 4.0