3103: Attribute 'DOCUMENT_ID' does not exist for item 'PORPOCHA/RESPONSE_67359_39381'

Issue:PORPOCHA workflow goes to error at activity "START_PO_APPROVAL" (Launch PO Approval workflow).
This happens in case of PO Change requests for MODIFICATION (Not for cancellation)

Details:
Item type: PORPOCHA
Activity: "START_PO_APPROVAL" (Launch PO Approval workflow)
Item key: RESPONSE_%
WF Error message:3103: Attribute 'DOCUMENT_ID' does not exist for item 'PORPOCHA/RESPONSE_67359_39381'.

Here, the change request gets stuck in the workflow at the node as mentioned above.

The PO status goes to "REQUIRES REAPPROVAL".
Not all the PO change requests (for modification) goes to this condition. Some complete successfully without any error.

Retry does not work in this case. If retried then the workflow remains in the error at the same node but the error message shows "ORA-06512: at line ".

Workaround: Ask the buyer to manually approve the PO.