[Bug] Built Assets include unused materials

[KnatteAnka]

Test 1:

Import Levee and build the mod.

Built mod is 12 KB

Test 2:

Add custom TimberMesh model.
And Declared the model
Built mod is now 5.419 MB

Test 3:

Remove Declaration of model
But Timbermesh still in Asset bundle but unused

Built mod is still 5.419 MB

TestMod.zip

Expected result:

Build a Small Asset bundle without any materials or textures because it should use base game items

Change compared to Base game example:

Using Exported materials to get base game textures in unity not just place holders with colors.