Checkbox manual select, after that dynamic deselect issue

components.my-child.js

import Ember from 'ember';

export default Ember.Component.extend({
   isChecked: Ember.computed('parentIsChecked',function() {
    return this.get('parentIsChecked');
  }),
  
});

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  service: Ember.inject.service('my-service'),
  isChecked: Ember.computed('service.watch',function() {
    return this.get('service.x');
  }),
  
  
  text: Ember.computed('service.watch',function() {
    return this.get('service.text');
  }),


});

components.my-links.js

import Ember from 'ember';

export default Ember.Component.extend({
   service: Ember.inject.service('my-service'),
  actions: {
    action(x) {
     this.set('service.x',x);
     this.set('service.text',x);
     this.set('service.watch',x);
      this.set('service.isAdmin',x);
    }
  }
});

controllers.application.js

import Ember from 'ember';

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

services.my-service.js

import Ember from 'ember';

export default Ember.Service.extend({
  x: 'checked',
  text:'text',
  watch:'',
  isAdmin:'',
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
Click button 1, click button 2, select last checkbox, click button 2
<br><br>
{{outlet}}
<br>
<br>
{{my-component}}
<br><br>
{{my-links}}

templates.components.my-child.hbs

Component child helper input: {{input type="checkbox" name="isAdmin" checked=parentIsChecked}}

templates.components.my-component.hbs

{{yield}}
<b>Parent component:</b><br><br>
Normal input: <input type=checkbox checked={{isChecked}}>{{text}} 
<br><br>
Helper input: {{input type="checkbox" name="isAdmin" checked=service.isAdmin}}
<br><br><br>
<b>Child component:</b>
<br><br>
{{my-child parentIsChecked=isChecked}}

templates.components.my-links.hbs

{{yield}}
<button {{action 'action' 'something'}}>Button 1</button>
<button {{action 'action' ''}}>Button 2</button>

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}