Mono Behavior of serializable reference type gets created when selecting a corresponding object in the Hierarchy window if it’s null and the Inspector window is set to Debug mode

How to reproduce:
1. Open the user’s attached “TestInsectorProject.zip” project
2. Open “SampleScene” Scene (Assets > Scenes)
3. Enter Play Mode
4. Change the Inspector’s mode to “Debug”
5. In the Hierarchy window, select “TestInsector” GameObject
6. Observe the Console window

Expected result: “Is null: True” is logged
Actual result: “Is null: False” is logged

Reproducible with: 2021.3.30f1, 2022.3.10f1, 2023.1.14f1, 2023.2.0b11, 2023.3.0a6

Reproduced on: macOS 13.5.2 (Intel)
Not reproducible on: No other environment tested

Note: not reproducible with “Normal” Inspector mode