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