Found a small UI bug. If a layer is a guide layer, is 3D, and is visible, the 3D switch’s icon goes away. If the layer is not visible OR is not a guide layer, the icon correctly returns.
In my screen shot, you can see layer 2 is missing the 3D switch icon, but still has 3D properties (Z position, orientation, Z rotation). All 3 layers are duplicates, otherwise identical besides guide/layer visibility.
System info Application: After Effects (Beta) v126.96.36.199 OS: macOS v10.15.7, RAM: 64.00 GB GB, CPUs (logical): 16