Highcharts Stacked Area Bug

HTML

<script src="https://code.highcharts.com/highcharts.js"></script>
<script src="https://code.highcharts.com/modules/exporting.js"></script>
<script src="https://code.highcharts.com/modules/export-data.js"></script>

<div id="container" style="min-width: 310px; height: 400px; margin: 0 auto"></div>

JavaScript

Highcharts.chart("container", {

    chart: {
        type: "area",
    },
    series: [{
            name: "Series 1",
            data: [156, 178, 206]
        },
        {
            name: "Additional Series which starts wit the last of Series 1",
            data: [
                [2, 103],
                [3, 126],
                [4, 129]
            ]
        },
        {
            name: "Additional Series which starts wit the last of Series 2",
            data: [
                [4, 65],
                [5, 96]
            ]
        }
    ],
    plotOptions: {
        series: {
        
            dataLabels: {
                enabled: true,
                style: {
                    fontWeight: "bold"
                }
            },
        }
    },
});