Hi Eric3
In AccountRight there isn't a report that shows when card details are edited or what was edited. You can restore from previous backups to view past snapshots of the card information, which can help with working out when the data was changed. Making regular backups will definitely help in this process.
Another method you can consider to better protect the data in the future is setting up Read Only access of supplier cards, so employees who should not be editing the card details doesn't edit it by mistake.
If you have any further questions please feel free to let us know.