How to reproduce:

1. Open the “UnityBugSearchUpdate.zip“ project
2. Select the “Cube“ GameObject in the Project and observe the Material object in the Mesh Renderer, then repeat with “Cube_Variant“ (they are the same)
3. Select the “Cube“ GameObject in the Project again
4. Change the Material object with “M_Test_02“ Material
5. Select the “Cube_Variant“ GameObject in the Project and observe the Material object (they are the same)
6. Right-click on “M_Test_02“ and select “Find references in Project“
7. Observe the Search window

Actual result: Only the “Cube.prefab“ GameObject is displayed as a result
Expected result: Both “Cube.prefab“ and “Cube_Variant.prefab“ GameObjects are displayed as a result

Reproducible in: 2023.3.0a2, 6000.0.63f1, 6000.2.14f1, 6000.3.0f1, 6000.4.0a5, 6000.5.0a2
Could not test in: 2023.2.0a1 (missing “Find references in Project“ context menu option)

Reproduced on: Windows 11 Pro (24H2)
Not reproduced on: No other environment tested

Notes:
- In 2023.3.0a2, the prefab variant never shows up unless its Material is overridden manually
- Reimporting the prefabs fixes the issue until the parent’s Material is changed again