Highstock : Previous data still displayed when cha

Question

Sorry for the english ...

I got a chart with custom data grouping. When I click to change the zoom, the new data are displayed over the previous one (which aren't deleted) :-(

rangeSelector : {
    allButtonsEnabled: true,
        buttons: [{
        type: 'month',
        count: 3,
        text: 'Day',
        dataGrouping: {
            forced: true,
            units: [['day', [1]]]
        }
    }, {
        type: 'all',
        text: 'Month',
        dataGrouping: {
            forced: true,
            units: [['month', [1]]]
        }
    }],
        selected: 2
},

I found a fiddle with this problem : http://jsfiddle.net/tqyyqmzs/12/

Month data are displayed. Click on "Day" or "week" and you will see that month data sill be on the graph :-(

P.S : One or two month ago, this code works. And now .... don't and I really don't understand why.

Did someone see the problem ?

Regards David

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Got the same problem on my website : https://www.bdpv.fr/en/ficheUtilisateur.php?util=boyardgo Click on panel "Production" Then click on zoom "Mois". Same behaviour, data for mois stay ...