Invisible Recaptcha data-callback function no longer being called!

[Anonymous Platypus]

I have a considerably large web app that makes use of Invisible ReCaptcha. The feature worked about 2 weeks ago but seems to have stopped working as of now.

The program makes use of Angular and CoffeeScript on the front-end and ASP.NET MVC5 on the back-end.

The g-recaptcha class is on a button. It calls an onSubmit function in the CoffeeScript. An example of the code is below:

<button class="btn btn-success g-recaptcha" data-sitekey="site_key_here" data-callback="onSubmit">
          <i class="fa fa-fw fa-refresh"></i>&nbsp;&nbsp;DO SOMETHING
</button>

I had to be quite hacky with the front to back-end code:

$window.onSubmit = (_token) ->     
  console.log "Trying reCaptcha"     
  $http.post "/api/captcha", null, headers: {"reCaptchaToken" : _token}      
    .then (res) ->         
      console.log "reCaptcha returned: ", res.data         
      if res.data == "Success"           
        console.log "Worked fine"          
        #DO STUFF         
      else
        grecaptcha.reset()      
   .catch () ->         
     console.log "reCaptcha failed"

I even tried putting a function in the HTML to check if the data-callback was firing:

<script>
  function onSubmit(token) {
    console.log("Callback fired!")
  }
</script>

Not getting anything back in the console.

If anyone has any ideas please share as I am at a loss and was hoping to take this feature live quite soon.

P.S. I am the juniorest of juniors and 100% open to any constructive criticism.

[Anonymous Platypus]

I should add it is Angular 1.4