[Solved]-Update datalabel on click of a point on the series of a highcharts timeline chart-Highcharts

It is probably a bug in timeline series. You can report it here: https://github.com/highcharts/highcharts/issues

As a workaround update userDLOptions instead of dataLabels.

point: {
    events: {
        click: function() {
            this.update({
                color: 'red',
                userDLOptions: {
                    enabled: true,
                    useHTML: true,
                    formatter: function() {
                        return 'sudheer';
                    }
                }
            });
        }
    }
}

Live demo: https://jsfiddle.net/BlackLabel/sf95dy2a/