To reproduce:
1. Open the project “IN-10787”
2. Select the Material “LayeredLit” in the Assets folder
3. Notice that two other Materials are attached to the Layer List in the Inspector
4. Duplicate the “LayeredLit” Material
5. Select the duplicate
Expected result: There are two Materials attached to the Layer List
Actual result: There are no Materials attached to the Layer List
Reproducible with: 2020.3.37f1, 2021.3.6f1, 2022.1.9f1, 2022.2.0b1, 2023.1.0a2
Reproduced on: macOS Monterey 12.4 (Intel)