Hello - we have been using IC functionality for a few years with Orders and recently noticed duplicate invoices being created. The duplicate issue was not appearing in 2022.

I will explain what we are doing.

1.  IC Partner X creates Sales Order (SO) and sends IC Sales Order.
2.  IC Partner Y receives a Purchase Order (PO).
3.  IC Partner Y posts the PO using Receive and Invoice. A posted purchase invoice is created.
4.  IC Partner X posted the SO using Ship and Invoice. A posted sales invoice is created.
5.  I navigate back to IC Partner Y and see another Unposted Purchase Invoice that was not present before step 4 was executed.
6.  I click on preview posting in the unposted Purchase invoice and receive a message that states /Posted invoice YYYYb originates from the same IC transaction as invoice YYYYa. To avoid duplicate postings, do not post invoice YYYYb. Do you still want to post invoice YYYYb?/.  I have inserted an image also.
7.  We can delete the duplicate however why is it being created in the first place?  Need some help.  Our setup worked in 2022 but now this is happening.

This scenario creates a duplicate purchase invoice when the sales order is posted. Even if the PO is not posted it will remain in a list of unprocessed PO's that will have to be deleted.