REST API for Project Cost Adjustment sometimes returns 'null' response for Split/Transfer operations

During Project Cost Split/Transfer operations, we’ve observed that both the APEX_WEB_SERVICE.make_rest_request API in Oracle APEX and the POSTMAN tool occasionally return a null response along with an HTTP 400 (Bad Request) statuscode. Despite this error, the expenditure split/transfer is successfully processed in Oracle, indicating that the backend operation completes as expected.

However, if we attempt to perform the same operation on the same expenditure item again, Oracle returns the following error message: "You can't perform this adjustment because adjustments aren't allowed on a reversed expenditure item.(PJC-2220014)", along with an HTTP 400 (Bad Request) status code.