How does Lockbox create customer bank accounts

We are on 11.5.10.2.

We get customer bank account numbers on our lockbox file, and also transaction numbers. Lockbox is set up to match on transaction numbers.

Lockbox is creating customer bank accounts, but somehow this is being done incorrectly. Some customers have several bank accounts where they are obviously incorrect (customer might be in New York, bank is in Nevada). Basically we don't care about this, as we don't use the bank accounts for anything, but it seems to cause problems with subsequent lockbox transmissions.

When the lockbox has both a transaction (invoice) number and a bank account that is associated with a customer different than the customer on the transaction, lockbox applies the money to the bank account customer ('on account').