Asset depreciation - Interest expense posted without a cost object

Dear experts,

Please help to how to resolve this issue.

I have some assets from a specific asset class. When I run AFAB to post depreciation, the interest expense also posted.

However, no cost center is a assigned in interest expense line item.

The below settings are in system:

- Cost center was already assigned to the asset masters.

- Transaction ACSET, the field cost center activated for transaction *, account assignment type (02 - depreciation run).

- Field status of posting key 40 - cost center is optional. The same setting for field status group in GL master.

- Cost element has been created for the G/L Interest Expense and validity is still valid.

Any suggestion is appreciated.

Dau Hai