QmlEaseFollow with a duration jumps

import Qt 4.6

Rectangle {
width: 800; height: 100; color: "gray"

Rectangle {
id: rect
width: 50; height: 20; y: 30; color: "black"
x: SequentialAnimation {
running: true; repeat: true
NumberAnimation

{ from: 50; to: 700; duration: 200 }

PauseAnimation

{ duration: 2000 }

NumberAnimation

{ from: 700; to: 50; duration: 200 }

PauseAnimation

{ duration: 2000 }

}
}

Rectangle {
width: 50; height: 20; y: 60; color: "blue"
x: EaseFollow

{ source: rect.x; duration: 500 }

}
}