How to reproduce:
1. Create a new project (any pipeline)
2. Import the attached “IN-137289Cat.fbx” and click on it
3. In the Inspector under the “Model” section, checkmark the “Generate Mesh LODs“ box
4. At the bottom of the Inspector, press “Apply”
5. Observe the crash

Reproducible with: 6000.3.11f1, 6000.4.0f1, 6000.5.0a9, 6000.6.0a1
Could not test with: 6000.0.71f1 (no Mesh LOD generation option)

Reproduced on: Windows 11
Not reproduced on: No other environment tested

Note: If the Mesh LODs have already been generated, uncheck the box, press apply, then start again from step 3

First few lines of the stack trace:
0x00007FFC6E0E905A (Unity) MeshLodUtils::BuildClusterMergeJobsGeneric
0x00007FFC6E104DA7 (Unity) MeshLod::SolveNextClusterLodLevel
0x00007FFC6E0F1D45 (Unity) MeshLod::BuildRedirect
0x00007FFC6E0DA2B9 (Unity) MeshLod::BuildClusterLodMeshFromMesh
0x00007FFC6E0D9A97 (Unity) MeshLod::BuildAndApplyClusterData