How to reproduce:
1. Open the attached “CrashRepro“ project
2. Open the “Assets/OcclusionCulling_Baked.unity“ Scene
3. Select the “Test“ GameObject in the Hierarchy
4. Enable it

Reproducible with: 6000.0.61f1, 6000.2.10f1, 6000.3.0b8, 6000.4.0a3

Reproducible on: macOS 15.6.1 Sequoia (Intel), Windows 11 (by user)
Not reproducible on: No other environment tested

Notes:
- The issue only reproduces if there is a “Directional Light” in the Scene with “Shadow Type” set to “Soft Shadows” or “Hard Shadows”
- The “Plane“ GameObject’s (child of the “Test“ GameObject) “Skinned Mesh Renderer” has “Update When Offscreen” enabled
- If “Occlusion Culling” is not baked, activating the “Test” GameObject does not crash Unity, but the entire Scene becomes shadowed (example in the “Assets/OcclusionCulling_NotBaked.unity“ Scene)