Customer PO field does not default to Receivables invoices from Sales Order when S/O is generated fr

Hi

When Customer PO field is entered manually in Sales Order, the info is populated in AR invoice-PO number field correctly.

However if the Sales Order generated from a Quote (the PO number field is populated in the  Sales Order) the PO number field does not populate to AR invoice.

Is this normal?

Thanks in advance

Prem