Looks like the network is acting per the transaction rule enabled. Check out this article to review the criteria's for 1 invoice against multiple deliveries -https://answers.sap.com/questions/7226058/combine-multiple-deliveries-in-one-invoice.html
Please refer to the response in this article and see if it helps you figure how to set up vendor and company code relationship in the ERP. https://answers.sap.com/questions/13220207/dsn-spro-configuration-enable-vendors-step.html
There was a very similar question posted on the community. Please refer to it and see if it resolves your issue. https://answers.sap.com/questions/13355456/reconcile-invoice-status-not-updating-arbcig-invoi.html
This looks like an intermittent system issue. Is this happening every time you create a return PO? Or is this happening with other transactions created too? As the message states clean your cache and cookies and see if that helps.
