Flickable.pressDelay causes buttons to not click

In the layout defined in the following code, if I press the button via the touchscreen, it registers the "pressed" property is set to 'true', but it does not change back to 'false' when I lift my finger, (and the clicked signal is never emitted). If I use a mouse, however, the button clicks correctly. 

If I remove the "pressDelay" line, then the button behaves correctly.

Flickable {
    width: 400
    height: 500
    pressDelay: 1

    Button {
        width: 400
        height: 100
        onClicked: print("this is never printed")
    }
}

If I replace the Button with a MouseArea, then presses are handled correctly.