Lockbox is creating Bank Account for Customers

Summary

Lockbox Receipts are imported and bank accounts are getting created for customer

Content

We are facing a unique situation where Lockbox is creating Bank Account for customers where bank account is not maintained. Receipts are getting matched to a different customers with same Transaction number. We have mapping to Transaction Numbers in the lockbox receipt file rather than customer bank account.

No bank accounts are maintained for our Customers. But mysteriously bank accounts are getting created by Lockbox for some customers on some occasions. We are not able to isolate the scenario to identify the root cause. 

Does anyone know of any hidden functionality of the Lockbox where bank accounts are created automatically for customers not having bank accounts.