Reproduction steps:
1. Open the user attached project
2. Select the "New Test Enum So" asset in the Project window
3. Change the "Simple Enum" value in the Inspector window
4. Reselect the "New Test Enum So" asset in the Project window

Expected result: "Simple Enum" value is what was set in step 3
Actual result: "Simple Enum" value is what it was before step 3

Reproducible with: 2020.3.25f1, 2020.3.34f1
Not reproducible with: 2019.4.39f1, 2020.3.24f1, 2021.3.3f1, 2022.1.1f1, 2022.2.0a14

Reproduced on: Windows 10, macOS 12.0.1 (Intel)