Necessary conditions to reproduce: OS language/locale set to a language that uses commas to separate numbers after the decimal point, e.g Lithuanian. Scripting Runtime Version and API Compatibility are set to .NET 4.x.
When creating an Exposed Color which is not completely white or black and attaching it to the Albedo property of PBR Master on PBR Graph, the Shader will fail to compile

How to reproduce:
1. Set your Windows language to a language which uses commas to separate numbers after the decimal point (for example Lithuanian)
2. Create a new project
3. Go to Edit -> Project Settings -> Player then set Scripting Runtime Version and API Compatibility Level to .NET 4.x
4. Go to Window -> Package Manager and download Lightweight Render Pipelines and Shader Graph
5. Create a new Lightweight Pipeline Asset and attach it to Scriptable Render Pipeline Settings
6. In the Project tab create and open a new PBR Graph
7. Create a Color, change the Color parameter to something other than complete black or white
8. Make sure the property Exposed is checked
9. Create a Node with that Color property
10. Attach it to PBR Master -> Albedo(3)

Expected result: The sphere in the example changes color to the chosen color
Actual result: The sphere in the example turns magenta

Reproduced on: 2018.1.9f1, 2018.2.3f1, 2018.3.0a8
Could not test on: 2017.4 or lower (PBR Shader Graph was introduced in 2018.1)