QSvgGenerator ignores QPen's MiterJoin joinStyle

#include <QPainter>
#include <QSvgGenerator>

const int w=100, h=100;
void test(QPaintDevice& dev)
{
    QPainter painter(&dev);
    painter.setBrush(Qt::darkGreen);
    painter.drawRect(0,0,w,h);

    auto pen=QPen(Qt::white,w/36.*4/w);
    pen.setJoinStyle(Qt::MiterJoin); // QSvgGenerator ignores this
    painter.setPen(pen);

    painter.scale(w,w);
    const QVector<QPointF> points={{0.4,0.6},{0.6,0.5},{0.4,0.4}};
    painter.drawPolyline(points.data(), points.size());
}

int main()
{
    QSvgGenerator generator;
    generator.setFileName("test.svg");
    generator.setViewBox(QRect(0,0,w,h));
    test(generator);
    QImage img(w,h,QImage::Format_RGBA8888);
    test(img);
    img.save("test.png");
}