leanpub.com: Item is missing in order if password is changed in between a purchase

Issue description:

• While trying to make a purchase in https://leanpub.com/ , just before checking out, if user changes the password with the same browser session, purchase is successful but the item is not added in the order / transaction.

Steps to reproduce:

1. Navigate to https://leanpub.com/
2. Try to find any free item like book to test this.
3. Do not login yet, just add the item in cart and proceed to check out
4. Enter registered email id in new account creation screen while check out
5. open a new tab in same browser and try to reset password
6. Return to checkout page, proceed with purchase
7. Observe that purchase is success but in order history the item is missing.
   

Expectation:

Item should have been added or a valid error message to be displayed to relogin with new session.