Cannot find Standard PO to receive in iProcurement

Our company recently began using Oracle iProcurement.  We are using version 12.2.5.

Sporadically, we are not able to see and receive a Standard Purchase Order in the iProcurement application.

I have already read note 135890.1 and ensured that all the data records meet the criteria from this note.  The only thing missing is the requisition.

What I do notice is that the two PO examples I have are not linked to a requisition via Auto Create.  Is this required?

If we have partially received against the line with a balance remaining, does that prevent the line from being retrieved and received for the remaining balance?