Checkout stuck step 2 (payment) on Firefox only

[miro91]

I have magento 2 running on live project and our clients are seeing some weird issue on Firefox browser. I was able to reproduce it only once and after refreshing the page everything is working as expected. I will be happy if someone have/had similar issue and have some information how to debug/fix it.

Preconditions

1. Magento CE 2.1.0
2. Production mode & Varnish
3. Firefox latest version

Steps to reproduce:

1. Add product to basket
2. Navigate to checkout page
3. Enter billing address and select shipping method
4. Click Next button to open payment section

Expected result:

Display loading-mask, load payment section and cart summary, hide loading-mask

Actual results:

Display loading-mask, load payment section and cart summary, loading-mask doesn't hide and stay.

No JS errors on console or network tab in FF (ajax request to getting payment section). After refresh with #payment in URL everything is working fine. Even if open /checkout without #payment (start from 1st step) it's opening 2nd step smoothly.

[dcabrejas]

I have exactly the same issue on Magento 2.1.0, it happens sporadically so I can't provide further details as to how to replicate it other than what @miro91 has already written. I can however tell you that for us, we have replicate it on Google Chrome and Safari so I don't think this is specific to the Firefox browsers. There is nothing in the logs nor in the browser console when the issue happens which makes it really hard, if not impossible to debug.

[Loxzibit]

I have the same issue on two different projects, one is running 2.0.9 and the other is running 2.1.0. Is there a solution for this?

@dcabrejasazagra @Loxzibit are your stores set in production mode?

[dcabrejas]

@jupiter01 I have managed to replicate this issue on both production and developer mode

[studiotwentyeleven]

We are also experiencing this issue on 2.1.0. As @miro91 said after refresh it works fine, we have found the issue across all browsers.

[SerhiyShkolyarenko]

@dcabrejasazagra @Loxzibit @studiotwentyeleven is a Varnish obligatory for reproducing?

[miro91]

@SerhiyShkolyarenko I can replicate it on local without Varnish. Also I was able to get this issue on Chrome, not only on FF

[dcabrejas]

@miro91 @studiotwentyeleven @SerhiyShkolyarenko I didn't use Varnish, I have put in place a quick work around for this issue : Override the following file in your theme : magento/module-checkout/view/frontend/web/javascript/model/shipping-save-processor/default.js
Change every instance of this line fullScreenLoader.stopLoader(); to fullScreenLoader.stopLoader(true); This will force the loader to stop, the true is for force.
Hope that helps.