I've noticed that the lumas shader, which can be used for multiple specular layers or
as a mask for light/unlit areas (for example, clearing wrong AO on lit sides)
doesn't work properly in Corona. I just noticed it when I was doing something that didn't have a volume around it.
Below are the examples.
1. AR: how it should work-unlit side is illuminated
2. CRN: without volume
3. CRN: with volume
4. usage examples (night side is lit)
Easy to reproduce, scene file provided.
Win 10, latest updates (everywhere)
R 19 latest, latest Corona build