Nesting 'Multi/Sub-Object' materials inside [material type] material is currently not supported.
This message occurs whenever scene contains Multi/Sub-Object material plugged inside of any of following materials:
- Double Sided
- Shell Material
Corona currently can not handle Multi/Sub-Object material nested in such materials.
Make sure there are no Multi/Sub-Object materials nested inside any multiple material mixer/combiner present in the scene.
See: Known bugs and limitations