Why do I get label displacement when I export a pie or line chart? - primefaces

Question

I have been trying to figure out why this happens for quite a while. My page have three kinds of charts: bar, line and pie models. The pie and line gets labels displacement when I export it and the bar its just fine.
I think it has something to do with jqplot css. But still, it is quite frustrating.
My pie chart is in a dialog...
xhtml code:
<p:dialog id="expanded-mission-distribution-dialog" resizable="false"
widgetVar="expanded-mission-distribution-dialog-var" modal="true"
dynamic="true">
<p:panel id="expanded-mission-distribution-panel"
styleClass="expanded-chart-panel ">
<p:chart id="expanded-mission-distribution-chart" type="pie"
styleClass="jqplot-target legend-spacing legend-size chart-dimension-3"
widgetVar="expanded-mission-distribution-chart-var"
model="#{fatigueDataSummaryAircraftAnalysisH.expandedMissionDistributionChart}" />
<p:commandButton id="mission-distribution-export-button"
type="button" icon="ui-circle-export" styleClass="ui-command-button"
title="Click to save the chart as image"
onclick="exportChart('expanded-mission-distribution-chart-var')" />
</p:panel>
</p:dialog>
The javascript that exports charts (I had to use a different approach compared to the one used in Primefaces' showcase, due compatibility purposes):
function b64toBlob(b64Data, contentType, sliceSize) {
contentType = contentType || '';
sliceSize = sliceSize || 512;
var byteCharacters = atob(b64Data);
var byteArrays = [];
for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
var slice = byteCharacters.slice(offset, offset + sliceSize);
var byteNumbers = new Array(slice.length);
for (var i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
var byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
var blob = new Blob(byteArrays, {type: contentType});
return blob;
}
function exportChart(chart) {
// Exportando o gráfico como uma imagem.
var image = PF(chart).exportAsImage();
var fileName = "image.png";
var src = image.getAttribute('src');
var type = 'image/png';
var b64Data = src.split(',')[1];
var blob = b64toBlob(b64Data, type);
var link = document.createElement("a");
if (link.download !== undefined) { // feature detection
// Browsers that support HTML5 download attribute
link.setAttribute("href", window.URL.createObjectURL(blob));
link.setAttribute("download", fileName);
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
} else {
alert('Chart export only works in Chrome (v20+), Firefox (Gecko v13+), IE (v10+), Safari (v6+) and Opera (v12.10+).');
}
Image of chart in dialog:
Pie chart inside my dialog
Image of exported chart:
Exported pie chart
There is nothing similar over internet or whatsoever, what could be the reason of this issue?