How to reproduce:
1. Open a new project with a Cinemachine package set up
2. Create a Prefab and attach a CinemachineSmoothPath component to it
3. Add a new Waypoint to it
4. Save the project and re-launch Unity
5. Check the Waypoints
Expected result: The recently added Waypoint is saved
Actual result: The recently added Waypoint is not saved
Reproducible with: 2.6.11, 2.8.9, 2.9.1 (2020.3.40f1, 2021.3.11f1, 2022.1.19f1, 2022.2.0b10, 2023.1.0a12)
Reproduced on: Windows 10
Note: Adding the Waypoint in the Prefab Edit menu or making changes to the coordinates of it after adding the Waypoint in the Inspector window does not reproduce the issue