How to reproduce:
1. Open the attached user project “22_Testing.zip“
2. Open Scene “SampleScene“
3. Observe the “BadTerrain“ GameObject

Expected result: The “DirtLayer“ painted textures on the “BadTerrain“ GameObject are rendered bright
Actual result: The “DirtLayer“ painted textures on the “BadTerrain“ GameObject are rendered dark

Reproducible with: 2021.3.21f1, 2022.2.11f1, 2023.1.0b8, 2023.2.0a6
Can’t test with: 2020.3.46f1 (Rendering Layers feature doesn't exist)

Reproduced on: macOS 13.0.1 (Intel), Windows 10 (by reporter)

Note:
- Issue is reproducible in Builds
- Issue is reproducible if Rendering Path is set to Deferred (in the “URP_Renderer“ asset)
- Issue is only reproducible with the fifth in line “DirtLayer“ Terrain Layer of the Terrains (the Layers can be seen by selecting the “BadTerrain” or “GoodTerrain” GameObjects and selecting the Paint Terrain symbol in the Terrain Component)
- If another Rendering Layer is added (by selecting the “UniversalRenderPipelineGlobalSettings“ asset and pressing the plus symbol below “Rendering Layers (3D)“), the “DirtLayer“ painted texture on the “GoodTerrain“ GameObject becomes dark, unless the Rendering Layer Mask is changed to have the “15 unused Layer” Layer (this can be done by selecting the “GoodTerrain“ GameObject, going to the Inspector, selecting the Terrain configuration options in the Terrain Component, scrolling down and selecting the mentioned Layer in the Rendering Layer Mask option under Lightmapping)
- Some Unity versions might need different Rendering Layers to be selected for the issue to reproduce