[Solved]-Highchart's Pie Chart Opacity Changes on Hover-Highcharts

You can change the opacity property in the inactive state:

plotOptions: {
    pie: {
        states: {
            inactive: {
                opacity: 1
            }
        },
        ...
    }
}

Live demo: http://jsfiddle.net/BlackLabel/05qwthgz/

API Reference: https://api.highcharts.com/highcharts/series.pie.states.inactive.opacity