Hi Babu,
Thank you for your reply but if you read OSS note 488725 mentioned by Thanga, message clearly says:
"During backorder processing, prepersistent quantity assignments are written as a result of the checks. When the backorder processing is then saved, the quantity assignments become persistent (the 'Backorder processing' transaction is thus completed). If this backorder processing is to be updated, the results are sent to R/3, updated there and then sent to APO using the core interface (CIF). In APO, the related quantity assignments are now imported by means of the update transaction and switched to postpersistent. Once the update is complete, the postpersistent quantity assignments are deleted. The postpersistent status is required to allow postpersistent quantity assignments to be switched back to persistent in the event of an error (that is, if the APO update encounters an error and is not committed). If the assignments are already deleted, they can no longer be restored."
And with my previous experience also I know BOP creates TQA and it remains in the system till CIF queue completes the update in ECC and comes back to APO.
Regards,
Anupam