Wrong Plant in the follow on document(PO) of SC in SRM

Hi Experts,

I need urgent input for this issue, We have SRM 7.0 and ECC 6.0 EHP5 with Classic scenario, We have created FO SC in SRM for the Plant A, After creating PO through SOCO, PO has wrong plant with the same company code, This issue is only in our production system and It is not reproducible in other systems. We have checked all possible places and configurations including org structure and custom changes. But no Clue. Plz plz plz..GIve me your valuable input on this. Awaiting your reply.

Thanks,

BR,

Basu