fillRect does not render correctly onto 16bpp image with scaling and antialias hint enabled

fillRect produce light blue/green line artifacts when rendering to 16bpp image with scale + antialias hints enabled
Test case:
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#include <QApplication>
#include <QPainter>
#include <QWidget>

class myapp : public QWidget
{
Q_OBJECT
public:
myapp(QWidget *parent = 0)
: QWidget(parent) {}

protected:
void paintEvent(QPaintEvent *event)
{
Q_UNUSED(event);
QPainter painter(this);
painter.fillRect(rect(), Qt::white);
QImage image(rect().width(), rect().height(), QImage::Format_RGB16);
QPainter mypainter(&image);
mypainter.setRenderHint(QPainter::Antialiasing, true);
mypainter.scale(0.873118, 0.873118);
mypainter.fillRect(rect(), Qt::white);
for (int i = 0; i < rect().height(); i+=6)

painter.drawImage(QPoint(0, 0), image);
}

};

int main(int argc, char *argv[])
{
QApplication app(argc, argv);

myapp mapp;
mapp.show();

return app.exec();
}
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