Vrayscattervolume causing checkerboard pattern

I’m creating a planetary cloud shader. It is quite simple. A vray displacement on a sphere and vrayvolumescatter with an opacity map in the overall colour slot.

For some reason there seems to be a checkerboard pattern appearing on the 0 opacity sections. It is more prominent when not using opacity or when changing the colour mode to scatter coeffienient + fog color

Any ideas what I can do to remove the pattern?


It seems raising sub-surface colour resolved this

Hi could it be a texture map tiling? It looks a bit like that.

do you have an inner surface on the sphere? could be z-fighting between coplanar faces where the displacement is not moving the faces apart.