JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.highcharts.com/highcharts.js"></script>
<script src="http://code.highcharts.com/modules/exporting.js"></script>

<div id="container" style="min-width: 310px; height: 400px; margin: 0 auto"></div>
<div id="container2" style="min-width: 310px; height: 400px; margin: 0 auto"></div>

JavaScript

$(function () {
    $('#container').highcharts({
        chart: {
            type: 'areaspline'
        },
        title: {
            text: 'Current behavior'
        },
        xAxis: {
            tickmarkPlacement: 'on',
            title: {
                enabled: false
            }
        },
        tooltip: {
            shared: true,
            valueSuffix: ' millions'
        },
        plotOptions: {
            areaspline: {
                stacking: 'normal',
                lineColor: '#666666',
                lineWidth: 1,
                marker: {
                    lineWidth: 1,
                    lineColor: '#666666'
                }
            }
            
        },
        series: [{
            name: 'Test1',
            data: [[1,2], [2,1], [3,2], [4,1], [5,3]],
            connectNulls: true
        }, {
            name: 'Test2',
            data: [[1,1], [2.2,1], [3,1], [4,1], [5,1]],
            connectNulls: true
        }]
    });
    
    $('#container2').highcharts({
        chart: {
            type: 'areaspline'
        },
        title: {
            text: 'Desired behavior'
        },
        xAxis: {
            tickmarkPlacement: 'on',
            title: {
                enabled: false
            }
        },
        tooltip: {
            shared: true,
            valueSuffix: ' millions'
        },
        plotOptions: {
            areaspline: {
                stacking: 'normal',
                lineColor: '#666666',
                lineWidth: 1,
                marker: {
                    lineWidth: 1,
                    lineColor: '#666666'
                }
            }
            
        },
        series: [{
            name: 'Test1',
            data: [[1,2], [2,1], [2.2, 1.16], [3,2], [4,1], [5,3]]
        }, {
            name: 'Test2',
            data: [[1,1], [2,1], [2.2,1], [3,1], [4,1], [5,1]]
        }]
    });
});