Chart JS time scale issue

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.13.0/moment.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.1.4/Chart.js"></script>
<div>
  <canvas id="graph" width="300" height="200"></canvas>
</div>

JavaScript

// 1468414757715 is "Wed Jul 13 2016 14:59:17 GMT+0200"
new Chart($('#graph'), {
  type: "line",
  data: {
    "labels": [1436878757715, 1436878758715, 1443515100000, 1443515101000, 1444913400000, 1444913401000, 1445239500000, 1445239501000, 1445326200000, 1445326201000, 1447314600000, 1447314601000, 1450879500000, 1450944000000, 1450944001000, 1452073500000, 1452073501000, 1452175200000, 1452175201000, 1452846300000, 1452846301000, 1453108500000, 1453108501000, 1459499700000, 1459499701000, 1466154900000, 1466154901000, 1468414757715],
    "datasets": [{
      "data": ["45", "55", 1204.232, "55", 1015.873, "55", 1054.544, "NaN", 1065.73, "NaN", 1066.176, "NaN", 1102.05, 1156.166, "NaN", 1009.441, "NaN", 1077.252, "NaN", 1101.638, "55", 989.327, "NaN", 2673.397, "NaN", 1635.959, "NaN", "NaN"],
      "label": "A",
      "fill": false,
      "lineTension": 0.1,
      "backgroundColor": "rgba(67, 154, 213, 0.7)",
      "borderColor": "rgba(67, 154, 213, 0.7)",
      "borderWidth": 1,
      "pointBackgroundColor": "rgba(67, 154, 213, 0.7)",
      "pointBorderColor": "rgba(67, 154, 213, 0.7)",
      "pointBorderWidth": 1,
      "pointRadius": null,
      "pointHoverRadius": null,
      "pointHoverBackgroundColor": "rgba(67, 154, 213, 1.0)",
      "pointHoverBorderColor": "rgba(67, 154, 213, 1.0)",
      "pointHoverBorderWidth": 1,
      "pointStyle": "circle",
      "type": "line"
    }, {
      "data": [686.247, "NaN", 1652.883, 1747.918, "NaN", 1711.563, "NaN", 1817.349, "NaN", 1866.92, "NaN", 1658.871, "NaN", 3555.429, "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", "NaN", 2633.001],
      "label": "B",
      "fill": false,
      "lineTension": 0.1,
      "backgroundColor": "rgba(127, 206, 187, 0.7)",
      "borderColor": "rgba(127, 206, 187, 0.7)",
      "borderWidth": 1,
      "pointBackgroundColor": "rgba(127, 206, 187, 0.7)",
      "pointBorderColor": "rgba(127, 206, 187, 0.7)",
      "pointBorderWidth": 1,
     ...