Caustics shadow bug

[Under-J]

Issue

You have 2 materials, each one assigned to a face of an object. One of them is transparent with a texture for transparency, and the other face has refraction with "Allow caustics" enabled. The shadow of the transparent face is solid.

System Setup (Environment)

RTX 3060 12GB, i5-10400, Windows 11, Blender 3.5.

Detailed Description

When "Allow caustics" is disabled, the shadow for the transparent face appears correct, while the shadow for the refractive face is missing. Here is an example:

If I enable "Allow caustics" to have shadows for the refractive face, the shadow of the transparent face becomes solid. Here is an example:

The next one is the expected behaviour, to achieve it: Mesh > Separate > By material:

So, when "Allow caustics" is enabled, it should produce correct shadows for both faces without requiring "Separate" like the previous example.

Also, when I check or uncheck "Refraction thin surface" || "Allow caustics", the render preview doesn't update, but it should.

Another thing, the final render crashed with the simple scene the first time only lol.

Caustic Bug.zip

Caustic Bug.crash.txt