This error is caused by a data mismatch between Pleo and our payment processor.
All balance data is synced daily (at around midnight) and that normally kicks the balance statement back into shape. Please try downloading your statement again the next day, and it should work. If you've waited until the next day and the balance statement download still isn't working, please contact our support team.
If you urgently need to check your running balance, you can always do so on the Export - Wallet page: