Finding existing receipts in receiving core forms

Hello,

We're using PO version 12.2.5.  When I try to search for a receipt by PO number using the Find Receiving Transactions core form, I get the message "FRM-40212: Invalid value for field PO_NUM."  I likewise get the message "FRM-40212: Invalid value for field RECEIPT_NUM" when I search by receipt number.

However, when I search for a receipt by a PO number using the Find Expected Receipts core form, the receipt appears.

Why is the search not working using the Find Receiving Transactions core form?

Thanks,

Debby