An invoice has been paid to a bank account that was never associated to the supplier

Hello!
An invoice has been created, approved and paid but the bank account details on the invoice are not associated to the supplier.  The payment has been voided but the issue still remains: how was that even the possible?

I have tried to replicate the issue but I can't change the bank account to another bank account when I am creating the invoice as that supplier only has one bank account. How did the invoice get paid to a supplier bank account that is not associated with the supplier?
The problem is on the 11i version of EBS.

Any help would be appreciated!