Card used for payment being made the default

[ghost]

Steps to reproduce

1. Make sure that user has atleast two credit cards, say Visa and MasterCard associated with his account and one of the two say Visa is the default credit card
2. Perform a checkout but during checkout use the non default card, in our case MasterCard for payment.

Expected behavior

Visa should stay the default card.

Actual behavior

MasterCard becomes the default card.

System configuration

Solidus Version: 1.4.2

Extensions in use

1. solidus_auth_devise
2. solidus_braintree

When order.next changes the order state from payment to complete, the card used for payment is automatically made the default. Why is the card used for payment forcibly made the default card ?. And, how can this be prevented ?

Thanks