title: Angular 2 ngFor changing values incorrectly at index + 2
body: <p>I have a form in angular. The form consists of a ngFor with a several selects. </p>
  
  <pre><code>&lt;div *ngFor="let item of items; let i = index"&gt;
    &lt;select name="" id="" [(ngModel)]="items[i]"&gt;
      &lt;option *ngFor="let option of options" [value]="option.value"&gt;{{option.display}}&lt;/option&gt;
    &lt;/select&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>And the data for this example: </p>
  
  <pre><code>options = Array(10).fill(1).map((option,index) =&gt; {
      return {
        display:'thing' + index,
        value: index
      };
    });
    items = [2,7,2,7,2,7,2,7];
  </code></pre>
  
  <p>The strange thing is that when I change the 2nd select the 4th select  will reflect the same change. However the model will not reflect this change. </p>
  
  <p>For what ever reason the view will change the the input 2 indexes after it to match. Even stranger this will only happen the first time then it will behave how you would expect. </p>
  
  <p>Here's the plunker to see the problem : 
  <a href="http://plnkr.co/edit/q1YnoPBFdBKm0JDMVk7Q?p=preview" rel="nofollow noreferrer">http://plnkr.co/edit/q1YnoPBFdBKm0JDMVk7Q?p=preview</a></p>
  
  <p>What would be causing this? How do I fix this issue?</p>