brians

We've confirmed its a 590 driver bug.
It turns out the KARMA_XPU_OPTIX_FORCE_OPTIXIR envvar may not solve the issue for you after all.
The good news is that I've committed a workaround in code which should work for you, its out in 21.0.594
cheers

> Do you have any source for that

Communication with NVIDIA engineers have confirmed it's a 590 bug, which should be fixed in 595.

> What else does this bug affect?

Not sure yet, it seems to be only affecting the kma_ramp nodes for now. A compiler glitch it seems.

> That would kinda influence my decision if rolling back drivers and recompiling all shaders again for hours is worth it to me.

I've committed a workaround for the issue to 21.0.594 (which will make its way into the next production build, hopefully this week).

But this change will trigger the need for a recompile anyway, so it's up to you if you...
- stay on 590, upgrade to 21.0.594(or later)
- roll back to 581.57, and stay on your current Houdini version.
(either way a recompile will be needed sadly)

It seem the NVidia 590 range of drivers have a bug.
What happens if you roll back to a 580 driver? (eg 581.57)