Alpha values in Gradient Editor Color Picker window are not editable

Reproduction steps:
1. Open project "Color_Picker.zip"
2. Open "ExampleScene" in Assets/Scenes
3. Select "Main Camera" Object in the Hierarchy Menu
4. In the Object's inspector window click on the blue-colored area in Camera -> Background component (opens Color Picker window)
5. Notice the Alpha value in the opened Color Picker window (= 0)
6. In the bottom of the Color Picker window -> Swatches click "add new preset"
7. In the Hierarchy Menu select "Example" Object
8. In the Object's Inspector window select "Picker Example" Script -> Color Gradient component
9. In the Color Gradient window click on the blue-colored area near the Color (picker) component
10. In the opened Color (picker) window click on the recently saved swatch box located on the bottom

Expected result: Alpha values in Gradient Editor Color Picker window are saved and are editable
Actual result: Alpha values in Gradient Editor Color Picker window are saved but are not editable

Reproducible with: 2020.3.17f1, 2021.1.19f1, 2021.2.0b9, 2022.1.0a6
Could not test with: 2019.4.30f1 (Picker Example file could not be loaded because it was serialized with a newer version of Unity)