How to reproduce:
1. Open the attached project (MaterialReflectionTest.zip)
2. Open scene Assets/Scenes/WorldGeneration
3. Press the Play button
4. In the Game view, navigate to where a water reflection of a GameObject is visible (controlled by WASD keys)
5. In the Hierarchy window, select the GameObject "BuggedCube"
6. Disable the GameObject "BuggedCube", or change its layer to "NotRendered", or change its Material from "Default-Material" to any other Material (in the Inspector window)
7. Observe the water reflections in the Game view

Expected result: the water reflections stay the same
Actual result: GameObjects are no longer reflected in the water

Reproducible with: 2020.3.19f1, 2021.1.22f1, 2021.2.0b12, 2022.1.0a9
Could not test with: 2019.4.30f1 (cannot resolve errors after downgrading the project: "Failed to load [files]. File may be corrupted or was serialized with a newer version of Unity.")

Notes:
1. The issue is reproducible on Windows
2. The issue is not reproducible on Mac, but the project loads with broken materials
3. On Windows, a shader error is thrown when opening the project (ErrorScreenshot.png)