I'm working on a groom in Houdini 19.0.498, and I'm seeing a strange "pinch" effect in the hair clumps created by a Hair Clump SOP. On some of the clumps, the hairs in the clump seem to converge to a single point before unconverging again.

Any idea what might cause something like this to happen, and how to work around it? The Hair Clump SOP has all of its default values, apart from Tightness, which is set to 0.55 rather than 1.0.

Dave.