Custom Reflection Probes sometimes revert to previous state following a bake

Steps to reproduce:

It's recommended to watch the reproduction steps video first [Internal link]

1. Download and open the attached project ([Internal link])
2. Open SampleScene
3. Navigate to Lighting window, and click on Generate Lighting
4. Once the bake had finished, select Plane and Sphere game objects, and mark them as Static
5. Generate lighting again
6. Select Reflection Probe - Custom GameObject, click on Bake button in the Inspector, and verify the output
7. Drag a green material on top of the Sphere or the Plane
8. Generate lighting again

Expected result:

• Custom reflection probe remains unchanged

Actual result:

• Custom reflection probe reverts to its previous state

Notes:

• Reproduces with CPU and GPU lightmappers
• Reproduces in all render pipelines
• Reproduces in Windows and macOS
• It's a very difficult issue to reproduce reliably