The trend is not displayed when using bestFitLine and dataloader plugins

The trend is not displayed when using bestFitLine and dataloader plugins

1.	Have:
Local Server Ubuntu 16.04
Windows Client with Google Chrome
CMS WordPress 4.9.6;
Latest Plugins:
amcharts-charts-and-maps;
dataloader
bestFitLine

2.	Let's consider a somewhat simplified example of a temporary chart with a trend line from https://codepen.io/team/amcharts/pen/0fc47f492f01aa42c3755e7da4a181f0.
html
<script src="https://www.amcharts.com/lib/3/amcharts.js"></script>
<script src="https://www.amcharts.com/lib/3/serial.js"></script>
<script src="https://www.amcharts.com/lib/3/themes/light.js"></script>
<script src="https://www.amcharts.com/lib/3/plugins/tools/bestFitLine/bestFitLine.min.js"></script>
<div id="chartdiv" style="width: 100%; height: 500px;"></div>
js
var chart = AmCharts.makeChart("chartdiv", {
    "type": "serial",
    "legend": {
      "useGraphSettings": true
      },

    "dataDateFormat": "YYYY-MM-DD",

    "valueAxes": [{
      "id": "v1",
      "axisAlpha": 0,
      "position": "left",
      "ignoreAxisWidth": true
    }],
  
    "graphs": [{
    "valueAxis": "v1",
    "bullet": "square",
    "bulletSize": 5,
    "valueField": "value",
    "fillAlphas": 0,

    "bestFitLine": {
      "lineColor": "#cc0000",
      "lineAlpha": 0.8,
      "lineThickness": 2
      }
    }],
  
    "categoryField": "date",
  
    "categoryAxis": {
      "parseDates": true,
      "dashLength": 1,
      "minorGridEnabled": true
   },
  
    "chartScrollbar": {},

    "chartCursor": {
      "cursorPosition": "date"
    },

  "dataProvider": [{
    "date": "2012-12-16",
    "value": 64
  }, {
    "date": "2012-12-17",
    "value": 61
  }, ..., {

    "date": "2013-01-30",
    "value": 81
  }]
});
Load the same data in JSON format using dataloader
html
<script src="https://www.amcharts.com/lib/3/amcharts.js"></script>
<script src="https://www.amcharts.com/lib/3/serial.js"></script>
<script src="https://www.amcharts.com/lib/3/themes/light.js"></script>
<script src="https://www.amcharts.com/lib/3/plugins/tools/bestFitLine/bestFitLine.min.js"></script>
<script src="https://www.amcharts.com/lib/3/plugins/dataloader/dataloader.min.js"></script>

<div id="chartdiv" style="width: 100%; height: 500px;"></div>
js
var chart = AmCharts.makeChart("chartdiv", {
    "type": "serial",
    "legend": {
      "useGraphSettings": true
      },

    "DateFormat": "YYYY-MM-DD",

    "dataLoader": {
      "url": "/json-data/ trend_data.json",
        "showErrors": true,
        "complete": function ( chart ) {
            console.log( "Loading complete" );
        },
        "load": function ( options, chart ) {
            console.log( "File loaded: ", options.url );
        },
        "error": function ( options, chart ) {
            console.log( "Error occured loading file: ", options.url );
        },
	"async": true
    },

    "valueAxes": [{
      "id": "v1",
      "axisAlpha": 0,
      "position": "left",
      "ignoreAxisWidth": true
    }],
  
    "graphs": [{
    "valueAxis": "v1",
    "bullet": "square",
    "bulletSize": 5,
    "valueField": "value",
    "fillAlphas": 0,
    "bestFitLine": {
      "lineColor": "#cc0000",
      "lineAlpha": 0.8,
      "lineThickness": 2
      }
    }],
  
    "categoryField": "date",
  
    "categoryAxis": {
      "parseDates": true,
      "dashLength": 1,
      "minorGridEnabled": true
    },
  
    "chartScrollbar": {},

    "chartCursor": {
      "cursorPosition": "date"
    }

});
chart.addListener("dataUpdated", zoomChart);
	zoomChart();
function zoomChart(){
    chart.zoomToIndexes(chart.dataProvider.length - 20, chart.dataProvider.length - 1);
}
The same json data file has the form:
[{"date":"2012-12-16","value":64},{"date":"2012-12-17","value":61}, ..., {"date":"2013-01-30",    "value":81}]
As a result we have the same chart, but without a trend line.
Please tell how to fix this problem.

Thank you