ActionScript 3.0 :: Poor Scaling When Drawing Some Long Lines Segments

I ran into a problem when attempting to draw long line segments - some lines will be poorly scaled and appear very thick. I ran into this issue when building a Google Maps Flex application and thought the problem resided there, but I then tested with a basic Flex application and duplicated the problem.

Here it is:
Code:
var _lineSprite:Sprite = new Sprite();
Application.application.rawChildren.addChild(_lineSprite);
_lineSprite.graphics.lineStyle(
6, // thickness
0xFF0000, //color
1.0, //opacity
true, //pixel hinting
LineScaleMode.NONE);
_lineSprite.graphics.moveTo(-70000,-20000);
_lineSprite.graphics.lineTo(400, 400);

The code above will draw a line segment that is much thicker than the desired 6 pixels. The problem can be seen here: [URL]. Once the page loads, click the "Show Custom Polyline" button, then the "Zoom to Problem Coordinates" button and you should see two line segments - one very thick and one thin. They should both be the same width as the thin line. Strangely, in the code sample I posted above, if the starting coordinates for the line are changed from -70000, -20000 to -70000, 20000 or to -140000, -40000 the line draws correctly. I'm using Flash Player 10.