Steps to repro:

1. Open the attached project and 'ProgressiveLightmappingExample' scene;
2. In the Hierarchy select 'Stalls01' gameobject;
3. In the Lighting window press Generate Lighting button;
4. In the Inspector quickly disable/enable Stalls01 gameobject.

OR

1. Download and open the 'BakingStallRepro' project and open the 'ProgressiveLightmappingExample' scene;
2. In the Lighting window enable Auto Generate checkbox for baking GI;
3. As soon as the ETA shows up in the progress bar in the Lighting window untoggle the Baked Global Illumination checkbox under the Mixed Lighting foldout;
4. Enable the Baked Global Illumination checkbox under the Mixed Lighting foldout.
5. Observe that the baking is stalled.

Expected result:
The lighting triggers the rebake and eventually bakes successfully.

Actual result:
Baking stalls. See attached repro video and Editor.log file.
Regression introduced in Unity 2018.1.0.

Workaround is to not toggle static flag of the baked gameobjects during the bake and, instead, do it between the bakes.

Notes:
- Reproducible in 2019.3.0a1, 2019.2.0a11, 2019.1.0f1, 2018.3.12f1, 2018.1.9f2;
- Not reproducible in 2017.4.25f1,
- Reproducible on Windows and OSX;
- Reproducible for Progressive CPU and GPU Lightmappers; not reproducible for Enlighten.