Reproduction steps:
1. Open the attached project named Case_1186500
2. Open the "Test" scene and select the Point Light 2D
3. Increase the Shadow Intensity slider
4. Observe the Scene view

Expected result: Scene grid behaves normally
Actual result: Part of the Scene grid gets shrunk and errors are thrown in the console window

Reproducible with: 2019.3.0b6, 2020.1.0a7
Could not test with: 2017.4.33f1, 2018.4.11f1, 2019.2.8f1

Reproducible with package versions: 7.1.1, 7.1.2
Could not test with package versions: 7.0.1 and below(Shadow Intensity option was not available)

Potential workaround: After upgrading to URP delete the existing LWRP asset used by the project and replace it with a fresh URP asset and 2D renderer

Notes:
1. For the issue to occur the project must be upgraded from LWRP to URP. Creating a new project with URP template does not cause the issue
2. The issue disappears once the Point Light 2D object is no longer visible in the Scene view.