Reproduction steps:
1. Open the user's attached "UnlitBatchingRepro.zip" project
2. Open the "BatchBroken" Scene
3. Enter Play mode
4. Open the Frame Debugger (Window > Analysis > Frame Debugger)
5. Enable Frame Debugging
6. Select the "Particle System (1)" draw call
7. Observe the panel to the right of the draw call list
Expected result: The draw call is batched, no such message as "objects are affected by different forward lights"
Actual result: A message says that this draw call can't be batched with the previous one because "objects are affected by different forward lights"
Reproducible with: 2019.4.36f1, 2020.3.29f1, 2021.2.12f1, 2022.1.0b8, 2022.2.0a5
Notes:
- Reproducible with Realtime, Mixed, and Baked Lights with the Built-in RP
- Does not seem to happen in either Universal RP or HDRP
- Tested with macOS