To reproduce:

1. Download and open attached "New Unity Project.zip" project.
2. In the hierarchy select "GameObject" gameObject and mark it as static.
3. When Unity asks if Children should also be marked as static, press yes.
4. Notice the error in the console.

Expected result: No error in the console is thrown when marking nested GameObjects as static
Actual result: InvalidOperationException error appears after marking nested GameObjects as static.

Reproduced with: 2018.1.0a3, 2017.3.0b10, 2017.3.0b1.
Not reproduced with: 2018.1.0a4, 2017.3.0a7, 2017.2.0p2.
Regression introduced in: 2017.3.0b1.

Tested with macOS Sierra version 10.12.6.

Notes: Did not reproduce on Windows machine.