Steps to repro:
1. Open the attached project and 'CornellBox' scene;
2. Let the scene auto-bake;
3. Observe the Scene view when the bake is completed.

Expected result:
Light probe gizmos are lit with the scene lights and the lightmap is rendered smoothly.

Actual result:
Light probes are black and the baked lightmap contains NAN artifacts. See attached screenshots.
The issue is introduced with the Light Probe Sample Multiplier feature in Version 2019.3.0a10.

Notes:
- Reproducible in 2020.1.0a2, 2019.3.0b1, 2019.3.0a12;
- Not reproducible in 2019.2.4f1, 2019.3.0a9 (the black probes issue);
- Not reproducible with the default light probe samples count (4);
- Reproducible on Windows;
- Reproducible only with the GPU Lightmapper, not reproducible with the CPU Lightmapper;
- Reproducible when baking with both area and emissive surface; not reproducible when baking either area light or emissive surface separately;
- The NaNs artifacts is not a regression and, possibly, should be logged in a separate case.