How to reproduce:
1. Create a new project
2. On projectview right click > Create > Shader > Unlit Shader
3. Select this shader and make sure you see it on inspector
4. Open the shader and edit it. just add random things to make sure it failed to compile
5. Save the shader and go back to editor

Expected result: Shader Inspector does not change and has correct error message as usual
Actual result: Shader Inspector UI displays repeated texture parameters and keeps adding more of them

Reproducible with: 2019.2.0a6
Not reproducible with: 2017.4.20f2, 2018.3, 2019.1.0b3, 2019.2.0a5