Probes lose their lighting data after entering Play mode when Baked and Realtime GI are enabled

Steps to reproduce:

1. Download the attached project and open SimpleOutdoorsA scene
2. Make sure that both baked and realtime GI are enabled in the Lighting settings
3. Make sure that Auto Generate is disabled in Lighting settings
4. Generate lighting
5. Enter play mode
6. Notice that light probes have lost their lighting data

Notes:

• Reproduced in: 2017.4.6f1, 2018.1.4f1, 2018.2.0b8, 2018.3.0a1 (330986351f8d), 2018.3.0a3 (0ac1bca97520)
• Affects both desktop and mobile platforms