Can't Match unorder receipt with Purchase Order

Dear Expert,

An unordered receipt was done for four items on of them we cannot match to a PO using "Match unordered receipt" function.

The receipt number is not appearing in the "Receipts" LOV although the Receiving Transaction Summary shows the transaction as "Unordered Receipts"

I have checked the Po and the receipt and the supplier match, item code match, receiving org match

I cannot find any issue, and both the receipt and the PO have 4 items all of which worked properly except for one.

Regards,

Ahmad Hamdan,