PO showing up for Release in ME28 even after deletion

Hello,

We have POs (doc.type NB) for which different release strategies have been set up.

Due to some business reason, buyer is cancelling the POs after the release is initiated.

(The flags set are delivery completed indicator, final invoice & deletion flag for PO item)

But, these deleted POs are still showing in the ME28 list for release.

This is causing quite a lot of confusion because the persons in the approving hierarchy are not aware of this deletion and are thinking they have to be released.

And the buyer has to inform them to ignore such POs. (Quite often, the approving persons happen to be senior management people)

The worst part is that system allows the concerned approvers to release the deleted POs with their release code.

Is this standard SAP behaviour?

Can something be done to prevent the deleted POs from showing in ME28 list?

On the other hand, is deleting a PO item after release has started, an acceptable business practice?

Should the buyer be advised not to do so? What is the correct business practice?

Regards

Prabhu