A customer payment has been entered for $10000 and applied against open invoices of exactly $10000. There are no short payments or overpayments. The amount of the payment matches the open invoice amounts perfectly in the payments screen. After saving, strangely, $10 shows as open on 1 invoice, and the payment of $10000 is showing that $10 is unapplied. We have tried deleting the payment and re-entering. We have tried opening the payment and typing the full open amount of the invoice in the payment screen and saving again. This doesn't help. The invoice still then shows as $10 unpaid and the payment transaction shows as $10 unapplied. Reporting is showing an open balance, it is not just in the customer transaction screen that this is showing. Any ideas to fix?