"PlayableGraph was not destroyed" warning is logged when entering the Play mode with the Prefab open (the prefab holds the script which creates PlayerGraph OnEnable() and destroys it OnDisable())

Reproduction steps:
1. Open the user's attached project and Test scene
2. In the Project window, double-click the Prefab
3. Observe that the PlayableScript script is creating PlayableGraph OnEnable and destroying it OnDisable
4. Enter the Play mode (with Prefab open)
5. Exit the Play mode
6. Observe the Console window

Expected result: No warnings are logged in the Console window
Actual result: Warning that PlayableGraph was not destroyed is logged in the Console window

Reproducible with: 2018.4.32f1, 2019.4.20f1, 2020.2.5f1, 2021.1.0b7, 2021.2.0a6

Notes:
1. When entering the Play mode OnEnable and OnDisable methods are called
2. Reproducible on Windows and not reproducible on macOS