This scene uses legacy (pre-v4) medium / refraction resolving that is not based on geometry normals and produces incorrect results when multiple medium containers are intersecting.
(But before, below the picture, read the translation from the official site coronarenderer.com)
Click "Switch to new medium resolving" and make a copy of the scene so as not to lose the old one!
Your scene is in version 4 below and uses an outdated resolution of the medium / refraction, which is not based on geometric normals and gives incorrect results when several medium containers intersect. The scene was loaded with inherited behavior to make the result more compatible with older versions of Corona, but we strongly recommend switching to the new behavior using the button. If the normal orientation is correct, switching will preserve or improve the appearance of the scene.
This message appears when using Corona Renderer 4 or later and when a scene created using Corona Renderer 3 or earlier is opened.
Ignoring or closing this message will result in an outdated medium / refraction permission, which means that:
The visualization will be more consistent with older versions of Corona. This is useful if you are re-rendering a scene that was originally rendered with Corona Renderer 3 or earlier. However, please note that we cannot guarantee that the results will be identical, as there may be some differences between the results of Corona Renderer 3 and Corona Renderer 4, even if using outdated resolution.
Additional effects may not display correctly or with artifacts, especially if two or more objects with volume effects or refracting materials overlap.
Clicking on the option “Switch to a new resolution of the environment” will update the scene to a new medium / refraction resolution of Corona Renderer 4, which means that overlapping objects with volume effects or refracting materials will render better (correctly), but they will look different than in the old ones versions of Corona Renderer.
Note 1: The way to resolve the environment can be changed even if the notification has been closed or accepted. To do this, go to the Development / Experimental Stuff deployment and check the "Use obsolete media resolution" checkbox in the "Basic Configuration" section.
Note # 2: This message will appear each time an older scene is opened until it is saved using Corona Renderer 4 or later. If you constantly receive this message when you open an older scene, then restoring this scene is the only solution to get rid of it. Please note that scenes saved with Corona Renderer 4 cannot be opened in Corona Renderer 3 or earlier.
All great renderings!