Rectangle Tool: problem with just one corner?

I don’t know if this is a known issue but I can’t seem to find a solution. This problem keeps arising and is rather annoying. When drawing a box with no fill using the rectangle tool some corners are not displaying properly. I like to change my corners to be square using “sharp corner” under “custom” and selecting “miter” under “join” in the properties palette.

However, the thing that is really bothering me right now is I have this one corner with a one pixel notch taken out of it. It is barely visible but the inconsistency really bothers me.

I have tried redrawing the shape, opening and closing flash, restarting my computer, changing the stroke to some ridiculous size and then bringing it back, zooming in and redrawing the spot back in…

Now in flash it looks fine but is still displaying with this notch removed when opened in a browser. (yes I have tried clearing my cache)

Any ideas?

thanks…