QML MessageDialog not properly shown on Mac

MessageDialog written in QML are not shown correctly on the Mac (although correct on Linux and Windows).

The bug is also referred in https://forum.qt.io/topic/93370/qml-messagedialog-on-macos-osx

The given workaround is no solution.

A simple example:

MenuItem { 
text: qsTr("About"); 
onTriggered: aboutMessage.open() 
}
 
MessageDialog {
id: aboutMessage 
title: "Licences used" 
text: { "LGPL & BSD" }
}

Output attached - the MessageDialog is "attached to the top", no title and cannot be moved.