In the below example, we can see there is a creditor invoice that has not been paid, and yet doesn't show up in the total owing column in the pay your creditors window: INV123
If you click Payment in the bottom right of the screen, you can expand on these, and we can see that there is a separate transaction for the same amount offsetting the $440.
In this example a journal was created for the opposing transaction.
If your situation does not match this example, please give our Helpdesk a call