Are there any changes in 18C that would affect invoice processing using Oracle Supplier Network with

Summary

New Supplier created as a trading partner is getting an error when the invoice is sent from OSuN to CMK.

Content

Are there any changes in 18C that would affect invoice processing using Oracle Supplier Network with CMK?  We are trying to test a new supplier and the configuration is identical to our suppliers in Production.  However we are getting the following error in CMK:

"The message cannot be processed because either Application Partner Code must be specified or all lines must have a Purchase Order number."

When we look at the message details, the Application Partner information is missing.