Auto Invoice Error: You can supply at most one Receivables account for a transaction

Dear All,

We have a grouping rule where grouping is only  by mandatory attributes.

We are not using Auto Accounting and are populating distribution records through a custom program.

After running Auto Invoice Master programfor a specific customer, we received the following error message: 

You can supply at most one Receivables account for a transaction (an invoice, a debit memo or a credit memo)

Scenario:

The customer has 3 sales orders for which a single AR invoice is to be generated.

2 sales orders have 1 delivery each and the 3rd sales order has 2 deliveries.

In the receiving distributions interface, we are having 2 entries for 2 deliveries of the 3rd sales order.