The new 2.5D displacement, introduced in Corona Renderer 5, works slightly differently from the old displacement and may produce undesirable results when applied to a Corona Light Material (such as artifacts or incorrect shading).
This can happen, for example, if an object using Corona Light Material has Cinema's Displacement Modifier enabled, or if displacement and Corona Light Material are used in a single Corona Layered Material.
- Remove the displacement entirely from the Light Material. (e.g. remove Cinema's Displacement Modifier from the object)
- Disable 2.D displacement in Render Setup > Performance tab. Note that this will revert displacement to the old displacement which may be deprecated in a future version, but the displaced light material should render fine.
- Use a regular Corona Material's self-illumination instead of a Corona Light Material.