I've had this problem with a few of the hairs as well. Correct gamma correction settings worsens it, and setting the texture filtering to Crisp doesn't help (Scenefixer is an integral part of my workflow, and I render no scene without running it). 

If the OP can't give a screen grab, I'll see if I can reproduce the problem tomorrow. 

花 | 美 | 花美 | 花火 
...It's a pun.