[TIMOB-2051] touchmove event on MaskedImage works STRANGE

I created an object by Titanium.UI.createMaskedImage,so,my be I can call the object MaskedImage,and I tried to move this object on a ScrollView,but it works so strange,I moved only 1 inch,but the image GONE!so i caught the e of the function,and found the x nearly not change,and the y grow so fast.
here's my code-----

var image = Titanium.UI.createMaskedImage({

height: 40,
width: 40,
image: 'chat.png',
mode: Titanium.UI.BLEND_MODE_SOURCE_IN,
zIndex: 2

});
image.addEventListener('touchmove', function(e){

Titanium.API.info('touch moving now ...');
Titanium.API.info(e);
var newX = e.x + image.animatedCenter.x - image.width / 2;
var newY = e.y + image.animatedCenter.y - image.height / 2;
image.animate({
    center: {
        x: newX,
        y: newY
    },
    duration: 1
});

});