Did anyone try the prepayment billing application?

Summary:

Did anyone try the prepayment billing application? I am trying the new option:

I am creating the "Prepayment Billing application" but whenever i generate the invoice , i am only getting negative line from the vent itself and not the invoice line from the prepayment event .

What is stating in the doc is : "

Generate Invoices process when run for the project contract will create a standard invoice with prepayment application invoice lines as illustrated below. 

while in my case it is only the application prepayment that is showing. Any idea?

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):