This message is caused by using Falloff map in “Shadow/Light” mode which is not supported by Corona. This feature, being non-realistic, would cause problems in photorealistic renderers such as Corona. Only the color/map used in “shaded” slot of the falloff map will be used.
Falloff map in "Shadow / Light" mode:
Falloff map in “Shadow/Light” mode present in the scene.
Remove offending falloff map, or set falloff mode to some of the supported modes.
See: Known bugs and limitations