Stripe - Payment Verification Step - 500 Error or Empty Cart when clicking `Continue` button while SCA Payment processing is happening

[grzeszet]

Context

It has been found that when user chooses SCA as a Payment Method and clicks Continue button on last checkout step, while checkout is processing SCA Payment theres 500 error happening or just a redirect to an empty cart without any information. There is quite a lot of time for user to click it, and skip the confirm page. Order have Completed Status, and Payment Status is Balance Due.

Focus on end of the video to see the issue:

https://user-images.githubusercontent.com/74255636/112325944-64518c80-8cb4-11eb-9a68-ef195defac69.mp4

Expected Behavior

Nor User, nor Guest should have the ability to click “Continue” button during Payment Verification - Continue button on Payment Verification should be inactive.

Actual Behavior

500 error or Empty Cart redirect when user clicks Continue while payment and order is being processed, no order confirmation page.

Steps to Reproduce

1. Add item to cart and go to checkout
2. Proceed to last step with SCA Payment
3. Click Place Order
4. Click Continue while payment is being processed
5. Notice 500 error or Empty Cart redirect

Your Environment

Affected version: spee.4.3.0.alpha (ruby 2.7.2; rails 6.0.0) Configuration: gem ‘spree’ gem ‘spree_gateway’ gem ‘spree_auth_devise’ gem ‘spree_static_content’ gem ‘spree_related_products’ gem ‘spree_sitemap’ gem ‘spree_analytics_trackers’ gem ‘spree_braintree_vzero’ gem ‘spree_i18n