Supplier Account Showing Incorrect Balance

I have a supplier account, which is set up using foreign currency, which displays the incorrect account balance in the card file (and anywhere that shows previews of AP balance). The AUD balance should be 32,834.83 (and this is shown on the payables reports), however in the card file it shows 27,929.76 owing AUD. When all bills are paid it shows a credit balance, even though the payables reports shows 0. The supplier has only been set up in this FY, so it is not a matter of opening balances or historical transactions.