QQmlFileSelector broken on Android with assets

We try to use another QML file on Android. But it looks like that the QFileSelector/QQmlFileSelector won't detect the correct +subdir.

We tried QQmlApplicationEngine with default QFileSelector and a replaced selector and added extraSelectors like "+test". Both won't work as expected.

The following example works from C++ code.
But QML will display "assets://qml/provider/ProviderDetailView.qml" instead of the "+test" file.
Same problem with default "+android" on Android!!

	QFileSelector* sel = new QFileSelector();
	sel->setExtraSelectors(QStringList() << "test");
	qDebug() << sel->allSelectors();

	mEngine.reset(new QQmlApplicationEngine());
	auto selector = QQmlFileSelector::get(mEngine.data());
	selector->setSelector(sel);

	qDebug() << sel->select("assets://qml/provider/ProviderDetailView.qml");

 ....
	mEngine->load(QUrl("assets://qml/main.qml"));

assets:/qml/provider/+test/ProviderDetailView.qml

Looks like this bug exists since at least two years:

https://forum.qt.io/topic/39642/qqmlfileselector-not-working-on-android-from-assets-folder

It works if we put every qml file into a qrc, compiles it to an rcc file and use "mEngine->load(QUrl("qrc:/qml/main.qml"));"