Steps to reproduce:
1. Download and open "Bug" project
2. Select "EXAMPLESHADER" in the Project window
3. Press "Open Shader Editor" in the Inspector window
4. Undock the Shader Graph window and place it next to Unity Editor
5. In the Editor, press Play

Expected result: Entering Play mode doesn't take 30 seconds, Shader Graph window doesn't stay blank for 30 seconds
Actual result: Shader Graph window stays unresponsive for around 30 seconds, Play mode loading takes around 30 seconds to load

Reproduced with: 2018.4.15f1, 2019.2.18f1, 2019.3.0f1, 2020.1.0a18 ("Shadergraph" package versions 0.1.17.preview - 7.1.7)
Could not test with: 2017.4 (No package manager)