GameObject reference is null when creating it inside Reset() function and assigning Script as a component when there is Timeline window opened in the Editor

How to reproduce:
1. Open user's project "ResetTest.zip"
2. Open "SampleScene" Scene
3. Click on "GameObject" in the Hierarchy window
4. In the Inspector window, right-click on "New Behaviour Script" and choose Reset
5. Observe console
6. Remove the "New Behaviour Script" component from the "GameObject"
7. Add "New Behaviour Script" Script from "Scripts" folder to "GameObject"
8. Observe console

Expected results: Same Console message (Generated GameObject (UnityEngine.GameObject)) after 4th and 7th step
Actual results: Console logs out null

Reproducible with: 2019.4.27f1, 2020.1.17f1, 2020.2.7f1, 2020.3.9f1, 2021.1.0a8, 2021.1.8f1, 2021.2.0a17
Couldn't test with: 2018.4 (Failed to downgrade to a functioning project)

Note: Closing Timeline window results in same Console message both after 4th and 7th step