Document VoxelGI static baking ignoring custom shaders and some properties

Author: Calinou

tutorials/3d/global_illumination/using_voxel_gi.rst

@@ -121,6 +121,22 @@ There are 3 global illumination modes available for meshes:
   This option is much slower compared to **Static**. Only use the **Dynamic**
   global illumination mode on large meshes that will change significantly during gameplay.
 
+.. note::
+
+    For meshes with the **Static** bake mode, the VoxelGI baking system is not able
+    to make use of custom shaders. These will be considered to be pure black,
+    only acting as light blockers. You can make custom shaders taken into account
+    by using the **Dynamic** bake mode for these objects, but this has a performance cost.
+
+    For BaseMaterial3D, some properties are currently ignored during baking. This can
+    impact visuals if the material's albedo or emission texture was designed around
+    a certain UV mapping:
+
+    - **UV1 > Offset**
+    - **UV1 > Scale**
+    - **UV1 > Triplanar**
+    - **Emission > On UV2**
+
 Additionally, there are 3 bake modes available for lights
 (DirectionalLight3D, OmniLight3D and SpotLight3D):