Hello! I don’t understand, with a material without any reflection, why the rendering (only with a sky) of the object (the crocodile’s head) is like almost metallic! Next to that, with exactly the same material, the platonic solid is quite normally matt!..???
Corona version, host software (and version), how the sky is set up, what the material set up is (screen grab)
Might you have a very, very very low sky intensitiy?
Might be something wrong with object’s normals. Try to reset them and see if that helps.
If the above recommendations fail, please contact us at support so we can test your scene. support@corona-renderer.com