Direct Connect Punchout - Editing UOM on the req line through punchout

FSCM 9.1 --  MP12.

For a Req line that is created through punchout, when we try to edit the req line, it takes us to the supplier's site (as expected).  If we update the quantity and checkout/punchout from the supplier's site, Req line quantity in PSOFT is updated (as expected).

But upon editing the Unit of Measure (say changing it from Each to Pack) in the supplier's site, we noticed that in PSOFT a new req line is added with UOM 'Pack' and existing line with UOM 'Each' remains unchanged. So, the user needs to delete the old req line with UOM 'Each'...