Reproduction steps:
1. Open the attached “IN-53998_LODBug (2).zip“ project
2. Open the “SampleScene”
3. Select the “ObjectWithLod” in the Hierarchy
4. Right-click on an existing LOD level (LOD 0 in the attached project reproduces the issue the most consistently)
5. Select "Insert Before" or “Delete” (“Insert Before” in the attached project reproduces the issue the most consistently)
6. Repeat the 4-5 steps until you achieve the “actual result” described below

Expected result: The “LOD Group” component does not get scrambled in the Inspector and no errors are logged in the Console
Actual result: The “LOD Group” component gets scrambled in the Inspector and an IndexOutOfRangeException is thrown in the Console

Reproducible with: 2021.3.30f1, 2022.3.9f1, 2023.1.13f1, 2023.2.0b9, 2023.3.0a5

Reproduced on: Windows 11 Pro (22H2)
Not reproduced on: No other environment tested

Workaround: Deselect and reselect the “ObjectWithLod” or add a new component in the Inspector (can remove it afterwards)

Notes:
- Reproduces approx. 1 in 30 times (highly variable) but performing the recommended reproduction steps for the attached project, should reproduce the issue from the first time
- Reproducible in a new project

Full error message:
IndexOutOfRangeException: Index was outside the bounds of the array.
UnityEditor.LODGroupEditor.DrawLODRendererMeshListItems (UnityEngine.Rect rect, System.Int32 index, System.Boolean isActive, System.Boolean isFocused) (at <2e279d988b9d4542841de511fbfdf8c2>:0)
UnityEditorInternal.ReorderableList.DoListElements (UnityEngine.Rect listRect, UnityEngine.Rect visibleRect) (at <2e279d988b9d4542841de511fbfdf8c2>:0)
UnityEditorInternal.ReorderableList.DoLayoutList () (at <2e279d988b9d4542841de511fbfdf8c2>:0)
UnityEditor.LODGroupEditor.DrawLODGroupFoldout (UnityEngine.Camera camera, System.Int32 lodGroupIndex, UnityEditor.SavedBool& foldoutState) (at <2e279d988b9d4542841de511fbfdf8c2>:0)
UnityEditor.LODGroupEditor.DrawLODGroupFoldouts () (at <2e279d988b9d4542841de511fbfdf8c2>:0)
UnityEditor.LODGroupEditor.OnInspectorGUI () (at <2e279d988b9d4542841de511fbfdf8c2>:0)
UnityEditor.UIElements.InspectorElement+<>c__DisplayClass72_0.<CreateInspectorElementUsingIMGUI>b__0 () (at <2e279d988b9d4542841de511fbfdf8c2>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)