So I don't know what happened but I'm getting all sorts of colorspace issues now that I wasn't having previously with Karma, maybe something changed with 20.0.590?
But simply, my viewport render isn't matching what's being put into the EXR anymore, and I need to know where to start to fix this. I know it's probably some OCIO/ACES stuff but I previously been get tripped up by it in other programs, and then struggle to get it to something I can make sense of.

Everything is set at defaults, I didn't add in any color space changes on the Karma Rop in Lops, I just placed it down as is.

So even just to get the ball rolling for me, what should I be changing where, to get things matching up again? As simply as possible too because I really can't make head nor tail of this stuff yet.

I was trying to figure how to do a panorama and found this thread in the process. So I'll put it here for future reference.

If you add a Karma Physical Lens Shader to the camera in Solaris you can set the projection to Polar on the Lens Distortion tab.

I've just started getting the exact same error as well, I'm trying to render fur on a character. What's the workaround?

EDIT: Just did a sweep on my curves, it's still pretty fast in my case but it definitely needs addressing.

While this may already have been figured out, I ran into this issue today and managed to fix it for myself. All I had to do was hit D (while hovering over viewport) and on the particles section of the geometry tab, make sure that display sprites was ticked off.
Oddly enough it only occurred when I plugged in a mocapbiped via a file merge into a geometry particle set-up, as opposed to a sphere.