Issue with CENVAT Clearing GL

Hi Xperts

While posting J1IEX after Goods Receipt , system updates the PO No & Line Item in the Assignment field of the CENVAT Clearing GL.However , while posting outgoing Excise Invoice via J1IV created via J1IS against 122 Material Document , system does not update anything in the Assignment field of the same CENVAT Clearing GL account.Why there is an issue , please advice.

Sort Key 010 has been assigned to the CENVAT Clearing GL.

Regards

Soumick