How to reproduce:
1. Open the attached project
2. Re-import "KeywordTest" shader
3. Check the console

Reproducible with: 2019.3.2f1 (7.1.8), 2020.1.0a24 (7.2.1).

Actual result: A lot of "internal error communicating with the shader compiler process" errors appears. (Full errors in edit)
Expected result: The shader graph compiles.

Notes:
- Removing any property and saving the shadergraph resolves the bug.
- Can't test ShaderGraph 6.9.2 and lower because the faulty shader graph fails to deserialise.
- Reproduces if you do this with handwritten (non - shader graph) shaders.