Hi Spine,
When using Skeleton Render Separator for a Skeleton Animation, if set the Mask Interaction to Visible Inside Mask or Visible Outside Mask, the materials of the Skeleton Parts Renderer doesn't updated to the correct materials.
I'm using spine-unity 3.8 (updated 2021-03-24).
Current workaround: Manually change the stencil comparison in the normal materials.
Thanks.