Png graph sometimes gets downloaded cropped

[icrestani]

I have this problem, not everytime, but 1/10 of the downloads the graph gets downloaded partially, i get only the top left part
the code I'm using to convert the graph to png it's the following:
var chart = AmCharts.charts[AmCharts.charts.length-1] chart.export.capture( {}, function() { this.toPNG( { multiplier: 2, }, function( data ) { pdf_layout.images[ "image_" + chart.id ] = data; this.download(data, 'test.png') } ); } );
I'm using AmCharts 3 if this can help