Fading objects not casting raytraced shadows correctly
 

I've attached the rendered image.

There's a keylight casting raytraced shadows directly on top.
There are two arrows. One bent and the other flat.
The flat arrow is casting the correct fading arrow.
The bent arrow's shadow doesn't fade completely at the end.

Any ideas why?

Opps. Here's the file

Without seeing the actual shader it's hard to tell. Is it a projection node or are you using UVs? It's just a wild guess, but if you are using a ramp to control your transparency, maybe it's set to wrap (tile), and what we're seeing is that ramp starting over again?

The ramp was set to repeat only once.
Here's the Maya 7 file.