Why system allows user approve/re-approve PO which has task was inactive at PO distribution?

Hi all,

For inventory item, I approved PO which has task number "001".

Then, I had revised PO to edit line quantity and this PO will require re-approve.

Before re-approve this PO, Cost Controller had inactive task number with input "Trans Finish Date" of task number "001".

Next, I approve this PO and system allows me to approve.

Why system allows user approve/re-approve PO which has task was inactive at PO distribution? Please advise.

Regards,

Pathikorn