Weird Grass Flickering

I’m using static particle strands as grass in an animated background in a game I’m making. For some reason, the color on the grass seems to flicker even though the lights don’t change, there is no material or texture IPO attached to the grass. You can see the animation here: Sorry about the large file size.

Doesn’t anybody have any idea how to fix this?

I did another test. The grass doesn’t do the weird flickery thing when ‘ray’ is turned off. So there must be something wrong with the raytracing.

Did another test. When tangent shading is turned off (and ray is turned back on) the flickering goes away).