Mac: Dragging an Item with Drag.dragType: Drag.Automatic does not send released signal on mouse up

When running the following example, wrong drag and drop behaviour can be observed along with a signal not being sent when it seems like it should:

import QtQuick 2.9
import QtQuick.Controls 2.2

ApplicationWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("Dragging rectangle")


    Rectangle {
        id: dragRectangle

        Drag.source:    dragRectangle
        Drag.active:    dragMouseArea.drag.active
        Drag.dragType:  Drag.Automatic

        width: 64
        height: 64
        color: "orange"

        Text {
            anchors.centerIn: parent
            text: "Drag this"
        }

        MouseArea {
            id: dragMouseArea
            anchors.fill: parent

            drag.target: dragRectangle

            onReleased: {
                console.log( "Mouse area released" )
            }
        }
    }
} 

Steps to reproduce:

1. Run the example
2. Drag the orange rectangle somewhere in the window

Expected behaviour

The rectangle is moved to the new position on mouse up, and stays there until another drag is started. The dragMouseArea onReleased handler is called on mouse up.

Actual behaviour

The rectangle is moved to the new position on moving the mouse after the drag. The dragMouseArea onReleased handler is not called until you click and release again. The entire GUI is unresponsive until you click the mouse to trigger the mouse release signal.

Additional information

If you comment out the line Drag.dragType: Drag.Automatic then drag and drop works differently (as expected) but also the onReleased handler is now called on mouse up after the drag.

I have tested this on older versions of Qt (5.9, 5.10, 5.11) and all of them work as expected.

You can also see this broken behaviour when running the externaldraganddrop Qt example app http://doc.qt.io/qt-5/qtquick-externaldraganddrop-example.html