How to reproduce:
1. Open the attached "IN-91971" project
2. Open the "SampleScene"
3. Observe the Scene and Game windows
4. Locate the “Point Light” object in the Hierarchy window and select it
5. In the Inspector window for the “Point Light” object, change the “Rendering Layers” Setting from “Light Layer 1” to “Default”
6. Observe the Scene and Game windows again

Expected result: Light Layers function the same way as the Default Rendering Layer
Actual result: Point Light is not applied to the Details found inside the “Terrain” gameObject

Reproducible in: 2021.2.15f1, 2021.3.47f1, 2022.3.55f1, 6000.0.33f1, 6000.1.0b1

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Notes:

* Also reproducible in Player
* Light Layers got introduced as a new feature with the release of Universal RP 12.0.0 and Editor version 2021.2.15f1. The issue does not reproduce in versions where Light Layers are not present
* Additionally, enabling Billboards in the Grass Texture causes the Point light to be applied as expected when using Light Layers