Invalid dash array processing on a path with multiple subpaths

#include <QGuiApplication>
#include <QPainter>

int main(int argc, char *argv[])
{
    QGuiApplication a(argc, argv);

    QImage img(200, 200, QImage::Format_RGB32);
    img.fill(Qt::white);

    QPainter p(&img);

    {
        QPainterPath path;
        path.moveTo(100.0, 30.0);
        path.lineTo(100.0, 80.0);

        QPen pen(Qt::red, 5);
        pen.setDashPattern({ 3, 3 });

        p.setPen(pen);
        p.drawPath(path);
    }

    {
        QPainterPath path;
        path.moveTo(20.0, 20.0);
        path.lineTo(160.0, 20.0);
        // This subpath's dash patter offset is incorrect.
        path.moveTo(100.0, 30.0);
        path.lineTo(100.0, 80.0);

        QPen pen(Qt::green, 5);
        pen.setDashPattern({ 3, 3 });

        p.setPen(pen);
        p.drawPath(path);
    }

    p.end();

    img.save("test.png");

    return 0;
}