XCB: Size of bold fonts changes between Qt 5.2.1 and Qt 5.3

When moving from Qt 5.2.1 to Qt 5.3 I recognized that the size of fonts inside of a Text element changes (gets bigger), if the font uses "bold: true". See attached picture for details.

Example Code:

Text {
text: "Unbekannter Name"
font.pixelSize: 20
font.bold: true
clip: true
}

I had to use font.pixelsize, because with font.pointsize the font sizes between the desktop (Linux Mint 64bit) and the android application differ way too much.

Talking about android: On android the bold fontsize is not affected.