EmberJS - Dynamic breadcrumb rendering (with action as variable)

breadcrumb.handlebars

<!----  Version 1 with #each -->
<ul class="breadcrumb">
  {{#each view.breadcrumbElements}}
    <li><a {{action lastObject href=true}}>{{firstObject}}</a><span class="divider">/</span></li>
  {{/each}}
</ul>

<!--- Version 2 with custom helper -->
<ul class="breadcrumb">
  {{renderBreadcrumb view.breadcrumb}}
</ul>

breadcrumb.js.coffee

App.Breadcrumb = Ember.Object.extend
  elements: null
  
  init: ->
    @_super
    @set('elements', [])
  
  reset: ->
    @get('elements').clear()

   # ....

breadcrumb_view.js.coffee

App.BreadcrumbView = Ember.View.extend
  templateName: 'general/breadcrumb'
  breadcrumbElementsBinding: 'App.breadcrumb.elements'
  breadcrumbBinding: 'App.breadcrumb'
  
  breadcrumbDimension: (->
    @get('breadcrumbElements.length')
  ).property('breadcrumbElements')

render_breadcrumb_helper.js.coffee

Handlebars.registerHelper 'renderBreadcrumb', (property, options) ->
  value = Ember.Handlebars.get(this, property, options);
  breadcrumbString = ""
  value.get('elements').forEach (element, index) ->
    breadcrumbString = breadcrumbString +
      "<li><a {{action #{element.get('lastObject')} href=true}}>#{element.get('firstObject')}</a>" +
      '<span class="divider">/</span></li>'
  return new Handlebars.SafeString(breadcrumbString)

When the breadcrumb should get rendered, the value of App.breadcrumb.elements is [ ['Start', 'showPortal'], ['Account', 'showPortalAccount'], ...] # Pair of Label and action name

In Version 1 I get Problems with giving the action as a variable ( lastObject ) and in Version 2 i get the right look of the rendered html but the links does not trigger the action (wrong href attribute set).
I.e. instead of

<a href='/portal'>Start</a>

i got

<a href='http://localhost:3000/true%7D%7D'>Start</a>

I tried a lot of different versions and none of them have worked, so i guess, iam doing something basic wrong, right?
Thanks for helping! ❤️