How to reproduce:
1. Open the attached project “ShaderWarning”
2. Build the project
3. Observe the Console

Expected result: There are no shader warnings in the Console
Actual result: “Shader warning in '<ShaderName>': Ignoring duplicate keyword line 'multi_compile _ DEBUG_DISPLAY'“ Warning is logged into the Console

Reproducible with: 2022.1.17f1, 2022.2.0b8, 2023.1.0a10
Couldn’t test with: 2020.3.40f1, 2021.3.11f1 (Scripts can’t be loaded)

Reproducible on: Windows 11 Pro

Note: Before opening and building the project, each time you need to delete the Library folder