QML WebView "icon" property doesn't work: doesn't change and doesn't emit a "onIconChanged" signal

In QML, the WebView.icon property doesn't work correctly, even though the C++ code looks OK to me.

The property is supposed to return a "QVariant(QPixmap)", and it seems to do. It returns a default "blue globe".
BUT it doesn't change when new URLs are loaded (either passing new ones or just clicking on links within the Webpage).

Tried with:
...
WebView {
...

Image {
id: testfavicon
anchors.left: parent.left
anchors.top: parent.top
}
...

onIconChanged: {
testfavicon.pixmap = icon;
}
}

Even using an alternative event (i.e. "onTitleChanged"), the even arrives but the icon doesn't change:
onTitleChanged: {
testfavicon.pixmap = icon;
}

Wee also WebKit bug https://bugs.webkit.org/show_bug.cgi?id=35414