How to reproduce:
1. Open “IN-93276_TestTerrainWarnings“ project
2. Select Terrain GameObject in Hierarchy tab
3. In Paint Trees section select Edit Trees > Add Tree > Plant_A
4. Paint trees on the Terrain in Scene view
5. Observe Console

Expected result: No warnings appear
Actual result: Shader warnings appear

Reproducible with: 2021.3.48f1, 2022.3.57f1, 6000.0.36f1, 6000.1.0b5, 6000.2.0a2

Reproducible on: macOS 15.2 (M1 Max), Windows 11
Not reproducible on: no other environments tested

Notes:
- In 2021.3.48f1, 2022.3.57f1 only one warning is present “The tree Plant_A must use the Nature/Soft Occlusion shader. Otherwise billboarding/lighting will not work correctly.”
- When you add a tree to the Paint Trees tool the Scene is marked as dirty and saving throws a warning again.