How to reproduce:
1. Create a new LWRP project
2. Right-click mouse in Project Browser > Create > Rendering > Lightweight Render Pipeline > Pipeline Asset
3. Edit > Project Settings > Graphics > Select RenderPipelineAsset > LightweightRenderPipelineAsset
4. Select the Main Camera in the Hierarchy
5. Change Background Type to Solid Color
6. Observe the Game View

Expected result: Game View is not overlayed by Camera's component Solid Color background
Actual result: Game View is overlayed by Camera's component Solid Color background

Reproducible with: 2019.2.0b8 (LWRP 6.9.1), 2019.2.6f1 (LWRP 6.9.1), 2019.3.0a9 (LWRP 6.9.1)
Not reproducible with: 2018.4.9f1 (LWRP 4.1.0), 2019.3.0a10 (LWRP 7.0.0), 2019.2.0b7 (LWRP 6.7.1), 2019.3.0b3 (LWRP 7.0.0), 2020.1.0a4 (LWRP 7.0.0)
Could not test: 2017.4.32f1 LWRP and Package Manager are not introduced

Note: Not reproducible on Windows