Steps to reproduce:

1. Download the attached project and open SampleScene
2. Navigate to the Lighting Settings window and make sure that only Realtime GI is enabled
3. Select Cube game object (the one with the red material), and make sure that Contribute GI is enabled, and Receive GI option is set to Lightmaps
4. Bake lighting
5. Notice that the cube contributes lighting to the surrounding realtime lightmap
6. Select Cube game object again, and set Receive GI option to Light Probes
7. Bake the lighting again
8. Notice that the cube does not contribute GI to the surrounding realtime lightmap

Notes:

- Does not affect baked GI; only realtime GI is affected
- This looks like an UI issue. As a suggestion, it would make sense to gray out Contribute Global Illumination option when both realtime GI is enabled, and Receive Global GI option is set to Light Probes