Stretch error when using 3D rotation

I have this problem when using “itemsname.rotationY” in as3:

In order to get around the blurring problem when using text with this function, I have made a 200% bigger version of what’s needed, and afterwards used a 50% version instead, but then:

When rotating to …let’s say 60 degree - no problem.

When rotating back to 0 degree - it stretches the movieclip on the Y-axis with almost 125%.

Anybody know why?

The code is simple:
import flash.events.MouseEvent;

function rotateNow(event:MouseEvent):void {
m1.rotationY = 0;
}
function rotateBack(event:MouseEvent):void {
m1.rotationY=40;
}

item1.addEventListener(MouseEvent.MOUSE_OVER, rotateNow);
item1.addEventListener(MouseEvent.MOUSE_OUT, rotateBack);