Dear Lovekush,
As DB Suggested they can be Temporary Quantity assignments instead use /SAPAPO/AC06 where you can get all other TQAs available in the system, or have a look at /SAPAPO/PEG1, and find out does there exists any inconsistent orders ( like with no characteristics ).
Hope this clue would help you to resolve the problem. Please update on same.
Best Regards
Arvind Pabba