[Card Processing] Lag between place order button click and UI loading indicator

[chickenn00dle]

There is about a 5-10 second delay between the time a user clicks the Place order button and the time the loading indicator appears: https://d.pr/i/pIfktD

Viewing XHR requests in dev tools, I can see requests happening, but on the front-end, it appears as though nothing is happening for a few seconds until the loading indicator finally appears.

If a customer selects the button a second time, a console error appears indicating payment is in progress, but again, nothing on the front-end: https://d.pr/i/wAf5pg

Steps to Reproduce

1. Make sure PayPal is connected and Credit Card Processing is enabled.
2. Add a product to cart and proceed to checkout
3. Select Credit Cards option and fill in all required form fields
4. Open dev tools and either navigate to the Network Tab or enable XHR messages in console
5. Select the Place order button. In dev tools, you will see magic happening. On the front-end, nothing will appear to be happening for a few seconds. Then the loading indicator will appear.

*This may be specific to my environment, but this doesn't happen with any other payment gateways for me.

[mattallan]

*This may be specific to my environment

I can confirm that I see the same thing :)