Application crashes when using Instantiator with asynchronous Loader

I am using an asynchronous Loader to load Qml components on demand.
When using ComboBox (QtQuick.Controls) in the loaded component, it fails to use its model. A minimal example is attached below.

With 5.1.1 (Windows 7, VS 2012 32bit) the combobox popup is empty and very small (about 1×1 px). The application keeps running.

I was able to reproduce the issue with Qt 5.2.0 in Debian Linux using Virtual Box.
If 3D acceleration is disabled (Virtual Box setting, mesa takes over i guess) the example works just fine. If 3D acceleration is enabled, the application crashes.

Please tell me if you need more information to reproduce this bug.

update
I simplified the example and removed the need for Controls. It can be reproduced with a basic Instantiator like this:

import QtQuick 2.2

Loader {
    asynchronous: true
    sourceComponent: Instantiator { model: 3 ; Item{}}
}