Actually your right it's some how wired. First of all I should mention that this scenario is happened just with one of our suppliers for specific type of procurement. (but 2 or 3 times every year)
Because of too many changes that happens during procurement, our purchasing department don't know the exact list of materials. so they just use 5 dummy materials for creating PR. after that (it may longs 6-10 months!) the packing list is send to the purchasing department by vendor. Now according to this packing list, PO document is created (of course without any reference to PR). It means that PR is not a practical document in our system.
I just try to find some way to attach PR to PO!
I thought maybe there is some way to
1- create PO like PR (with these dummy material)
2- receipt real materials during the process of inbound delivery (with help of packaging instructions witch are created according to packing list)
Best Regards