In this image you see two renderings of the same scene, one at the default rendering settings (left) and one at "Final" with displacement maps and smooth polygons also turned on (right).

Notice how the lower quality render shows the hair with a good transparency map while the high quality render shows it all solid.

Any ideas what's going on here? I now realize that I ran into this once before with this hair, so I don't think it's something unique to this scene. Is this a known problem? I should point out that I'm something of a newbie to prop hair since I usually use dynamic hair.

If it matters, I'm running P6, sp2.