Paying Transaction Type field on the Criteria tab of a Saved Search causing duplicate results for transactions.

On a Transaction Saved Search on the Criteria tab and Standard sub-tab having a filter called Paying Transaction : Type might result in certain Invoices are appearing twice when running the search. Possible reasons why this can occur:

1. The Invoice has more then one payment applied to it.
2. One of the payments applied to it has a Discount applied to it.