Order in other currency

Hello,
we are using your CURCY premium plugin. All works great, we are using it for informational purpose, convert price only in the shop, all checkouts are still made in EUR. Works great, till we yesterday got one order in converted currency in value of EUR, underneath was value in EUR in red color and converted in ratio with converted currency. Order was done with “Payment via Direct bank transfer” not credit card. Why would this happen, thankfully it was only one order now. I’ve tested and cannot replicate the issue.