Item cost is showing as zero

Hi Guru's,
I have performed PO receipt and received items into inventory. Distributions are also generated for the receipted items.

But when I am performing any Issues, the cost of item is getting calculated as zero.

When I checked the item cost history(Navigation Cost Management - SLA > Item Costs > Item Cost History) it clearly shows the transactions were done containing the cost.  But it in the same form in the new quantity block the details are not created.

I am enclosing screenshot for your reference.

Thanks,
Gopi Nath