Roboto Light font doesn't render nicely on Linux when QML Item::scale isn't 1

The issue is in Qt 5.4.1 (see top line of Qt5.4.1.png i.e. "light") and has been fixed in 5.5.0-beta (compare with Qt5.5.0.png), but is still in today's (May 19) 5.4.2 snapshot:
http://download.qt.io/snapshots/qt/5.4/5.4.2/2015-05-19_131/qt-opensource-linux-x86-5.4.2_2015-05-19_13-47-35-131.run

It does not occur on Mac nor Windows (nor on Linux with scale: 1). Ubuntu 14.04 is where I see it.

It can be reproduced with the attached fonts.zip file (which includes three .ttf files) by running FontTest.qml in qmlscene (and resizing the qmlscene window via mouse drag makes the issue even more apparent):

import QtQuick 2.4

Column{
    scale: 0.9
    
    FontLoader{source: 'Roboto-Light.ttf'}  
    FontLoader{source: 'Roboto-Regular.ttf'}
    FontLoader{source: 'Roboto-Bold.ttf'}   

    Text{text: font.family;  font{pixelSize: 36;  family: 'light'}}    
    Text{text: font.family;  font{pixelSize: 36;  family: 'regular'}}    
    Text{text: font.family;  font{pixelSize: 36;  family: 'bold'}}      
}

You shouldn't need them, but the original fonts can be obtained from here:
https://www.google.com/fonts/download?kit=hY6_qqcqX_JNp8IlbByiXfesZW2xOQ-xsNqO47m55DA

I modified the .ttf files' font family names in fonts.zip with FontForge due to bug 30851
http://fontforge.github.io/en-US/downloads/