Alpha question in Flash MX 2004

Hey Everyone,

When placing a movie clip over another movie clip, both having the same color and attributes applied, why can you see the edges when tweening from alpha 0% - alpha 100%
(as seen in the attached example)?

In theory, shouldn’t you see nothing?

I’m not sure if this is specific to MX 2004 (or if it has been resolved in v.8), but if anyone has any fixes, I’d appreciate the help.

Thanks!