Can't build due to unclear shader compilation errors and warnings when Built-In Target is used in Shader Graph

How to reproduce:

1. Open the user’s attached project “SGBugs.zip”
2. Build the project
3. Observe the Console window

Expected results: Project successfully builds
Actual results: Project fails to build and errors with warnings occur

Reproducible with: 12.1.7 (2021.3.6f1), 13.1.8 (2022.1.9f1), 14.0.3 (2022.2.0b2), 15.0.0 (2023.1.0a6)
Could not test with: 10.10.0 (2020.3.38f1) (“Cannot find the code for this Target, a package may be missing”)

Reproducible on: Windows 10

Notes:

• Removing the include shouldn't be necessary since that "guards" against multiple imports with an ifdef anyways, and without it types/autocomplete don't work properly anymore when working on the cginc file
• Can successfully build and run after commenting out the 19th line in “PBRHelpers.cginc” or removing the Built-in target from "MyShaderGraph"