Changes to one form item in a dom-repeat gets copied to the bottom item

[Nate Thompson]

In the web component below, if I make to entries by clicking add twice then change the upper entry, the change to the upper entry gets copied to the bottom one.  Am I doing something wrong, or is this a bug?

<link rel="import" href="/components/polymer/polymer.html">

<link rel="import" href="/components/paper-button/paper-button.html">

<link rel="import" href="/components/paper-input/paper-input.html">

<dom-module id="medatest-test">

  <template>

    <paper-button on-click="_addClicked">Add</paper-button>

    <template is="dom-repeat" items="{{data}}">

      <paper-input value="{{item}}"></paper-input>

    </template>

  </template>

  <script>

    Polymer({

      is: "medatest-test",

      properties: {

        data: Array,

      },

      attached: function() {

        this.data = [ ];

      },

      _addClicked: function(e) {

        this.push("data", null);

      },

    });

  </script>

</dom-module>

Thanks,

Nate