Drilldown issue in Orgchart Highcharts - Formating Links

I started exploring highcharts. Created report with organization hierarchy with drilldown. Unable to format the links in drilldown report, they look like triangles instead of straight lines like in the main org chart and getting messy when the hierarchy in the drilldown gets multiple nodes.

In below example, click on Div.2, see the drilldown links. What chart options do we have to control these triagle svg shapes other than linkLineWidth etc..

Links with Triangle Shape

jsfiddle Test Case

Highcharts.chart('container', { chart: { height: 600, width: 600, inverted: true, type: 'organization' },

title: {
    text: 'Highcharts Org Chart'
},
series: [{
    name: 'Highsoft',
     data: [{
            from: "CO",
            to: "DIV01",
        },
        {
            from: 'CO',
            to: 'DIV02'
        } 
    ],
    nodes: [{
            id: 'DIV01',
            title: 'Div Hd 1',
            name: 'Div. 1',
            drilldown: "DIV01"
        },
        {
            id: 'DIV02',
            title: 'Div Hd 2',
            name: 'Div. 2',
            drilldown: 'DIV02'
        } 
    ]
}],
drilldown: { 
    activeDataLabelStyle: {
        color: 'contrast'
    },
     layout: 'hanging',
    series: [{
            id: "DIV01",
            name: "DIV01",
            keys: ['from', 'to'],
            data: [
                ['DIV01', 'DEP01']
            ],
            nodes: [{
                id: 'DEP01',
                title: 'Dept Hd 1',
                name: 'Dept. 1' 
            }]
        },
        {
            id: "DIV02",
            name: "DIV02",
            keys: ['from', 'to'], 
            data: [
                 ['DIV02', 'DEP02'],
                 ['DEP02', 'DEP03'],
                 ['DEP02', 'DEP04'], 
                 ['DEP04', 'DEP05'],
                 ['DEP04', 'DEP06'] ,
                 ['DEP04', 'DEP08'] ,
                 ['DEP06', 'DEP07'] 
            ],
            nodes: [{
                id: 'DEP02'   
            }]
        } 
    ]
} 

});