Stripe.js: «Can only create one Element of type cardNumber»

I’ve tried making an order and I still get JS errors in console, but they are a bit different: https://www.dropbox.com/s/ybvw33kc11yha2s/Screenshot%202017-11-15%2017.20.32.png?dl=0
Also, when I change country from United States to something else, more JS errors appear and clog wheel keeps spinning indefinitely… https://www.dropbox.com/s/09ps14ntu5qx5c0/Screenshot%202017-11-15%2017.22.26.png?dl=0
Can you please make sure that the order process works and that clients can complete the payment?

It looks like your browser caches an old JavaScript.
I have checked the country switching scenario too: it does not change the bank card fields.

I’ve just checked and creating order doesn’t work. I’ve started filling in all the fields and I get the same clog wheel on the screen: https://www.dropbox.com/s/k9qu55q0qf38yaj/Screenshot%202017-11-15%2017.36.42.png?dl=0

Have you really cleared the full browser cache?!
The simplest way is to check the «Disable cache» checkbox in Chrome:

My cache is disabled and I still can’t create an order: https://www.dropbox.com/s/k2no4d44bw21lc9/Screenshot%202017-11-15%2017.51.35.png?dl=0
Can you try to complete test order?

I have fixed the «Can only create one Element of type cardNumber» issue.
This issue was caused by the HS_OneStepCheckout module.
It reloads the payment form on country changing.
Unfortunately, there is no way to preserve the previously entered bank card data after such reload, because Stripe dynamically creates an IFRAME for each bank card form element, and it does not allow any JavaScript to access the entered values (for security reasons).

https://github.com/mage2pro/stripe/issues/52