Steps to repro:
1. Open the attached project and 'SampleScene' scene;
2. In the Lighting window (Window>Rendering>Lighting) press 'Generate Lighting' button;
3. Wait until the lighting is baked;
4. As soon as the light baking is completed in the Hierarchy select Cube gameobject;
5. Delete the Cube gameobject;
6. In the context menu select Edit>Undo.

Expected result:
The cube has the baked lightmaps on it (i.e. it's lit).

Actual result:
The cube's baked lighting is lost, it's black. See attached screenshot.

Notes:
- Reproducible in 2020.2.0a2, 2020.1.0a26, 2019.3.3f1, 2019.2.21f1, 2019.1.14f1, 2018.4.18f1;
- Reproducible on Windows and OSX;
- Reproducible when the GI baking is set to manual mode, not reproducible with the auto-bake mode.