This was caused by the material indices not referring to an existing material slot. Clamping the value to the maximum material index for the given object fixes the issue. Pull Request: https://projects.blender.org/blender/blender/pulls/138544
This was caused by the material indices not referring to an existing material slot. Clamping the value to the maximum material index for the given object fixes the issue. Pull Request: https://projects.blender.org/blender/blender/pulls/138544