transition bug

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

controllers.posts.post.js

import Ember from 'ember';

export default Ember.Controller.extend({
  queryParams: ['subscribe'],
  subscribe: null,

  shouldShowSubscribeModal: Ember.computed('subscribe', {
    get() {
      return this.get('subscribe') === 'true';
    },
    set() {
      this.transitionToRoute({ queryParams: { subscribe: null } });
    }
  }),
  actions: {
    unsubscribe() {
      this.set('shouldShowSubscribeModal', true)
    }
  }
});

router.js

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('posts', function() {
		this.route('index', { path: '/'})
    this.route('post', { path: ':id'})
  })
});

export default Router;

routes.posts.index.js

import Ember from 'ember';

export default Ember.Route.extend({
});

routes.posts.js

import Ember from 'ember';

export default Ember.Route.extend({
});

routes.posts.post.js

import Ember from 'ember';

export default Ember.Route.extend({
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
{{#link-to 'index'}}Index{{/link-to}}
<br>
{{#link-to 'posts.index'}}Posts index link{{/link-to}}
<br>
<br>
{{outlet}}

<br>
<br>

templates.posts.index.hbs

{{link-to 'single post' 'posts.post' 'something'}}
<br/>
<br/>
{{yeild}}

templates.posts.post.hbs

This is post
<br>
Subscribe: {{subscribe}}
<br>
<br>
{{link-to "subscribe here" (query-params subscribe=true)}}

<br>

{{#if shouldShowSubscribeModal}}
	This is should show when on subscribe route
	<button {{action 'unsubscribe'}}>Close this section</button>
{{/if}}

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}