Post Processing effects are functional when they are toggled Off and not functional when they are toggled On

How to reproduce:
1. Open the user's attached "Granville.zip" project
2. Open the "SampleScene" Scene
3. Select the "Main Camera" GameObject
4. Add "Lens Distortion" override in the Post-process Volume Component
5. Toggle the "Off" button in the "Lens Distortion" override
6. Adjust the Intensity property of the "Lens Distortion" override
7. Observe the Game view

Expected result: Lens Distortion override is not updated when it's toggled Off
Actual result: Lens Distortion is updated when it's toggled Off and is not updated when it's toggled On

Reproducible with: 2020.2.0a7, 2020.2.2f1, 2021.1.0b2, 2021.2.0a2 (3.0.1, 3.0.2)
Not reproducible with: 2018.4.30f1, 2019.4.18f1, 2020.2.0a5 (3.0.1)