Is this behavior of SpringAnimation normal?

[ealione]

Have a quick look at the code below. If you run it and spam the button, you will notice that it wont return to its desired position. This wont happen if you click it slowly and wait for the animation to finish.

If instead of a SpringAnimation animation you use PropertyAnimation then the problem disappears.

Is this normal, or a bug ?

import QtQuick 2.2
import QtGraphicalEffects 1.0

Item {
    id: menuButton    
    state: "Closed"

    Rectangle {
        id: menuButtonIcon
        anchors.centerIn: parent
        //color: Qt.lighter("#C02A25", 1.25)
        color: "#D23F31"
        width: 65;
        height: 65;
        radius: width * 0.5
        antialiasing: true
        visible: false;
    }

    DropShadow {
        id: menuButtonIconShadow
        source: menuButtonIcon
        anchors.fill: source
        width: source.width
        height: source.height
        cached: true
        radius: 8.0
        samples: 16
        color: "#60000000"
        smooth: true
        horizontalOffset: 0.0
        verticalOffset: 0.0
        spread: 0.2
        transparentBorder: true
    }

    Rectangle {
        id: menuButtonIconBar1
        anchors.centerIn: menuButtonIcon
        width: 17
        height: 3
        antialiasing: true
    }

    Rectangle {
        id: menuButtonIconBar2
        anchors.centerIn: menuButtonIcon
        width: 17
        height: 3
        antialiasing: true
        rotation: 90
    }

    MouseArea {
        id: mouseArea
        anchors.fill: menuButtonIcon
        onPressed: menuButton.state = menuButton.state === "Open" ? "Closed" : "Open"
        //onClicked: menuButton.state = menuButton.state === "Open" ? "Closed" : "Open"
    }

    states: [
        State {
            name: "Closed"
        },
        State {
            name: "Open"
            PropertyChanges { target: menuButtonIconBar1; rotation: 135; scale: 0.92}
            PropertyChanges { target: menuButtonIconBar2; rotation: 225; scale: 0.92}
            PropertyChanges { target: menuButtonIconShadow; scale: 0.92}
        }
    ]

    transitions: [
        Transition {
            //RotationAnimation { target: menuButtonIconBar1; properties: "rotation"; duration: 400; easing.type: Easing.InOutQuad }
            //PropertyAnimation { target: menuButtonIconBar2; properties: "rotation"; duration: 400; easing.type: Easing.InOutQuad }
            //PropertyAnimation { target: menuButtonIconShadow; properties: "scale"; duration: 400; easing.type: Easing.InOutQuad }
            SpringAnimation { target: menuButtonIconShadow; properties: "scale"; spring: 3; damping: 0.25; epsilon: 0.2; mass: 1; modulus: 0; velocity: 0 }
            SpringAnimation { target: menuButtonIconBar1; properties: "rotation, scale"; spring: 3; damping: 0.25; epsilon: 0.5; mass: 1; modulus: 0; velocity: 0 }
            SpringAnimation { target: menuButtonIconBar2; properties: "rotation, scale"; spring: 3; damping: 0.25; epsilon: 0.5; mass: 1; modulus: 0; velocity: 0 }
        }
    ]
}