Reproduction steps:

1. Open 'repro_avs.zip" project
2. Select "Sphere Baked" and "Cube Realtime"
3. "Vertex Stream Injector" -> "Inject color data in AVS"
4. Notice that in the left side of Scene view there is text: "AVS Name Injected_AVS"
5. Generate Lighting
6. Notice that in the left side of Scene view there is text: "No AVS found"

Expected Result: Baking Lightmaps doesn't erase existing Additional Vertex Streams

Reproduced with: 2019.3.0a1, 2019.2.0a13, 2019.1.0f2, 2018.3.14f1
Did not reproduce on: 2017.4.26f1