Reproduction steps:
1. Open the user's attached project and test scene
2. In the Hierarchy window, expand LightLayerTest and select both Point Light Red and Point Light Blue
3. Observe the Sphere in a Game view

Expected result: Sphere is affected only by red light
Actual result: Sphere is affected by red and blue lights

Reproducible with: 7.5.2 (2019.4.19f1), 10.2.2 (2020.2.2f1), 11.0.0 (2021.1.0b2, 2021.2.0a2)
Not reproducible with: 2018.4.31f1 (could not downgrade HDRP)

Notes:
1. Reproducible with Spot, Point and Area Lights
2. With HDRP 7.5.2, GameObject is affected by red and blue lights
3. With HDRP 10.2.2 and 11.0.0 GameObject is not affected by any lights
4. Reproducible on Windows and Mac