QPainter::drawText with rotated painter has incorrect spacing on Windows only

On Windows only, the spacing between characters is often incorrect when using QPainter::drawText with a rotated QPainter. In the test application below, the drawn strings should be identical except for a small, almost unnoticeable rotation. As it is, it is clear that the spacing between the "w"'s and "i"'s is way off.

#include <QtGui>
#include <QFont>

class MyWidget : public QWidget {
public:
  MyWidget(QWidget *parent = NULL) : QWidget(parent) {
    setFixedSize(100, 100);
  }

protected:
  void paintEvent(QPaintEvent *) {
    QFont f;
    f.setFamily("Arial");
    f.setPixelSize(11);

    QPainter painter(this);
    painter.setFont(f);
    painter.setBrush(Qt::NoBrush);
    painter.setPen(Qt::SolidLine);
    painter.drawText(50, 50, "wiwi");

    painter.rotate(1.);
    painter.drawText(50, 70, "wiwi");
  }
};

int main(int argc, char **argv) {
  QApplication app(argc, argv);
  MyWidget w;
  w.show();
  return app.exec();
}

A screenshot of what this looks like on my machine is attached. Some things I have noticed:

• It is fine on X11 (Ubuntu, at least) and Mac OS X.
• It only affects certain fonts at certain sizes. If, for example, you change the font in the example to pixel size 12 or point size 11, it looks fine.
• This may be a duplicate of QTBUG-20900. It certainly seems like the same behavior. I wasn't positive, however, so opened up a second bug and added reciprocal links.