I had similar problems, so asked here, I was advised to try the following: Lower the shading rate of the hair item to something between 0.02 to 0.05 - select the neck of the hair item and then properties and you'll find the shading rate. Then in the render settings lower the shading rate to match that of the hair item. eg. you set the hair to 0.02, so set the shading rate to 0.02. This works for me every time, if like the Sassy Hair it's a prop item you can still set the shading rate as above. I avoid using texture filtering because Firefly just craps out on me.