Customers cannot switch from Payment's payment methods to non-Payment methods

During checkout, when choosing one of Payment's payment methods and subsequently choosing a non-Payment payment method, Payment still tries to execute a payment for the order using its lastly selected payment method.

Steps to reproduce:

1. Set up a Ubercart web shop that has at least one paymet method through Payment enabled and one payment method that does not come from Payment. Also enable Payment for Ubercart.
2. Add products to the cart and go through checkout.
3. Select the payment method that is provided by Payment.
4. Select a payment method that is not provided by payment.
5. Complete checkout

Depending on the exact type of the Payment payment method, you will either see that a payment is being made using it, or you can check the order's payment status to confirm this.