Answer
Rather than using a raw raise_application_error() call, use the framework's own Error_SYS package instead (for example Error_SYS.Appl_General('<YourLuName>', '<ERROR_CODE>: <your message>')) — Error_SYS is specifically designed to integrate with IFS's own background-job error-reporting mechanism, producing a properly readable, correctly formatted error message visible in the background job's log, whereas a bare raise_application_error() call may not surface in the expected user-visible way when the calling code is executed as a background job rather than run directly.