Because I think this is still an issue, here a simple demo to reproduce the issue
The code will render differently on Mac and Windows (both with same physical pixel scales).

class BoxDemo : public juce::Component
{
public:
BoxDemo() { setTransform (juce::AffineTransform::scale (1.33)); }
void paint (juce::Graphics& g)
{
g.fillAll (juce::Colours::white);
g.setColour (juce::Colours::black);
g.fillRect (10, 2, 2, 2);
g.fillRect (20.f, 2.f, 2.f, 2.f);
}
};
