We have football field scene done in Houdini 20.5. Generating one patch of grass and duplicating it over the field. We use flat ribbon for grass blades. When switched to Hoduini 21, we started getting strange normal glitches on grass, moving camera back, grass just changes normals...

Here is grass blade rendered in Houdini 20.5 with flat ribbon mode:


Here is same grass blade in Houdini 21:


And here is same grass in Houdini 21, rendered as rounder curves:


We use Houdini 21.0.512.
Is there something we miss here?

Attachments:
curve_ribbon_hair_shader_h20_5.jpg (32.0 KB)
curve_ribbon_hair_shader.jpg (40.2 KB)
curve_rounded_hair_shader.jpg (34.0 KB)

Attachments:
curve_ribbon_problem.hip (817.3 KB)