Texture animation bug?

What are the known texture animation bugs?
Does this look familiar to anyone?

3 screenshots at different distances

This is in world at Rose (62, 134) (room #603) but I'm not sure if it's entirely reproduceable. The first time I noticed this I had come back to the area after leaving it for awhile (maybe this is cache related?)

I don't know if leaving the area and then returing later is a factor or not, but this seems to occur more when you look at the animation up close. The odd thing is that if this corruption is visible for a long time (as it usually is) and you zoom out, it will become less visible and eventually disappear entirely. I tried to show that in the screenshots at the above link. It's like the green stuff becomes "more transparent" until eventually at a distance it isn't visible at all and the animation looks normal.

It's not easily reproduceable (maybe I'll figure it out eventually) but it seems to be fixed after I relog, and only seems to appear after I've been logged in for awhile.

Information about how the animation is made:
I used two 1024x1024 animation sequences, one loads+plays, and then a second loads+plays. Both have about a 2 second delay before they begin playing to give texture loading a head start. Script is still a work in progress, though.

I can't rule out that the script I wrote is the cause of this since I wrote it from scratch and I've never seen an animation script before, but I kinda doubt that's the cause.

In case it's hardware related:
driver- RADEON 9500 PRO/9700
Updated to latest catalyst etc etc..

aww..nobody's seen this before?