COMAPI errors after upgrade to 2018

I've inherited an old .NET application that uses the ACCPAC.COMAPI to create orders in ACCPAC.

Since the client has upgraded to Sage 300 2018, the application is returning a 'Error HRESULT E_FAIL has been returned from a call to a COM component' error.  The application is able to create the header record, but during the detail creation it returns that error, specifically when it tries to set_value for the ITEM.

Any advice or suggestions on why this is happening?

Thanks