White Edge Artifacts on Solid Layer Shadows in After Effects Advanced 3D Renderer

While testing 3D shadows using two solid layers in After Effects' Advanced 3D Renderer, I encountered an unusual rendering issue:

When the two solid layers are close to each other, intersecting, or even perfectly overlapping in 3D space, a noticeable white edge/white line appears along the edges of the shadow cast by one of the solid layers.

The issue can occur under the following conditions:

1. The two solid layers have a certain amount of spatial distance between them;
2. The two solid layers intersect each other in 3D space;
3. The two solid layers are completely or almost completely overlapping;
4. With the Advanced 3D Renderer enabled, and lighting and shadows turned on, an abnormal white edge can be observed around the boundary of the shadow.

In particular, the white edge still appears when the two solid layers are completely overlapping or geometrically intersecting. Therefore, this does not appear to be caused simply by the distance between the layers or by normal layer occlusion.