Purchase expenditure for product account is showing some balance

Hi,

I have few POs which are INVOICED but when I check invoice voucher its showing Purchase Expenditure Production account Debit but not showing Its credit side due to which some amount is appearing in this a/c.

After looking into further I found for all such PO invoices system is keeping ZERO COST AMOUNT in Item detail >>Transactions>> filter that PO = purchased = showing cost amount zero

or even if I check PO >>Invoice [voucher] > cost Transaction ...its showing zero.

any idea about this ?? I have already run inventory closing but no luck.

thanks,

Faiqa