Flash graphics glitch with alpha transparencies: any ideas what could be going wrong?

[scc]

Hey folks, this forum has found me loads of answers in the past through various searches but now it's time for me to enquire about something myself...

Here's a bit of graphics I'm going to be using as part of a larger project:

http://server1.stillhost.com/~stucox...ogoGlitch.html


You'll see that as the mask for the logo at the top seems to bite a chunk out of the mask on the arrows below (they've got an alpha mask on them to make them fade towards the top)... this is just a graphics glitch as if you get it to redraw that frame, it redraws fine.

What could cause this? it's almost as if the two masks (the one on the logo and the one on the arrows) are adding/subtracting together, even though they're in totally different layers of heirarchy, have different instance names, etc

I know that the issue is the masks as if i disable either one or the other, it renders fine. I've also noticed similar things in other areas of my graphics with two coinciding masks causing glitches.

The one solution I've found (short of removing my transparency, but I want to keep that as part of the design!) is to make the movieclip containing all of the arrows to move very slowly (at least one pixel per frame seems to do it), which seems to stop the glitching - no idea why, other than that it might be forcing it to redraw properly?

I've tried playing around with the bitmap caching on just about every movie clip in the movie and all sorts...

Any thoughts?

[scc]

No one?