An AP invoice names a subcontract whose status is Refused. 422. Nothing is posted.
OPDC API error code
SUBCONTRACT_REFUSED
HTTP status 422
The API answers with a problem document (RFC 9457) whose type is https://twinn.engineering/errors/subcontract-refused, and with X-Error-Code: SUBCONTRACT_REFUSED. Branch on the code, never on the detail text.