Ionic 1.3.1. ION-NAV-BUTTONS is broken

To Reproduce:

index.html

<body>
  <ion-nav-bar>
      <ion-nav-back-button>
      </ion-nav-back-button>
    </ion-nav-bar>
</body>

View - 1

<ion-view view-title="View - 1">
  <ion-content>
    <button ui-sref="view-1">VIEW 1</button>
  </ion-content>
</ion-view>

View - 2

<ion-view view-title="View - 2">
  <ion-nav-buttons side="right">
    <!-- Add a few buttons here -->
  </ion-nav-buttons>
</ion-view>  

Please provide a more complete example. I am not able to see anything wrong.