How to reproduce it:
1. Open the attached project "1292639.zip"
2. Open the “Test.unity” file with the Visual Studio
3. In Visual Studio find the "m_CompositePaths" object
4. Notice that "m_CompositePaths" object doesn't contain empty brackets ("- []")
5. In the Unity Editor, load the "Test" scene
6. In the Hierarchy view, select the ‘GameObject’
7. In the Inspector view, find and remove Composite Collider 2D
8. Add a new Composite Collider 2D component to the 'GameObject'
9. Save the “Test” scene
10. In Visual Studio observe the "m_CompositePaths" object

Expected result: "m_CompositePaths" object doesn't contain empty square brackets ("- []")
Actual result: Empty square brackets ("- []") appears in the "m_CompositePaths" object

Reproducible with: 2019.3.0f1, 2019.3.15f1, 2019.4.15f1, 2020.1.17f1, 2020.2.0f1, 2021.1.0a9
Not reproducible with: 2018.4.30f1, 2019.3.0b12