3365327 - When Using the Querycustomerinvoicein Service, GTIN is not Returning

 You are using the QueryCustomerInvoiceIn, however, the system is not returning the GTIN value maintained in the item master data.

SAP Business ByDesign 

This is the system expected behavior. 

The GTIN field is not present for Customer Invoice, hence no GTIN value is saved in a Customer Invoice document.
Also, as this is not present in the document structure, the same will not return when performing a query.

As a potential solution, you can create an extension field to store this value and extend it do the desired service.  

GTIN, Customer Invoice, Webservice, QueryCustomerInvoiceIn, Missing , KBA , AP-CI-CI , Customer Invoice , Problem