Repro Step:
Create a plane and apply a subsurface material to it. Position it as a wall close to the camera.
Create a pointlight and place it behind the plane. Observe the light through the plane.
Drag a mesh between the plane and the light. Confirm shadows casting through the plane.
Change the lighting channel of ONLY the plane and the light to 1. Leave the Mesh on 0.
Observe the shadow for the mesh disappear due to not being on the channel the plane and light are on. (Optional: add channel 1 to the mesh to see the shadow reappear to test).
Apply nanite to the mesh and observe the shadow reappear no matter what you do.
Am I doing something wrong? All of my meshes are using Nanite so my test here has been to check “Disallow nanite” on the asset details for the mesh and then it behaves normally.