Reproduction steps:
1. Open the attached project “PropertyFieldBug“
2. Open the scene “Assets/Scenes/SampleScene”
3. In the Hierarchy window select the GameObject called “SerializedFieldBug”
4. In the Inspector window modify the “Serialized Transform” property field value
5. Set the “Serialized Transform” property field value to “None”

Expected result: Value can be changed back to “None”
Actual result: The property field cannot be set to null

Reproducible with: 2022.2.0a17, 2022.2.1f1, 2023.1.0a24
Not reproducible with: 2020.3.43f1, 2021.3.16f1, 2022.2.0a16

Reproducible on: Windows 11