How to reproduce:
1. Create a new project
2. Select 'Main Camera' GameObject
3. Create a child GameObject with Alt+Shift+N
4. Right-click on the created GameObject and select 'Set as Default Parent'
5. Undo with Ctrl+Z
6. Redo with Ctrl+Y
7. Right-click on the child GameObject

Expected result: 'Set as Default Parent' is not redone with the same action as the child creation
Actual result: 'Set as Default Parent' is left after redoing the child creation

Reproducible with - 2020.2.0b2
Not reproducible with (No 'Set as Default Parent' functionality) - 2018.4.25f1, 2019.4.8f1, 2020.1.0b1