How to reproduce:
1. Open the project "case_1217708-DomainReloading"
2. Open the scene "SampleScene"
3. Disable Domain Reloading in the Project settings
4. Select "Child" Prefab in the Prefabs folder in the Project window
5. Change the value in the Value field in the Child (Script) component in the Inspector
6. Press CTRL + S while the input box is still selected
7. Press the Play button
8. Observe the results in the Console window

Expected results: no exceptions are thrown
Actual results: the exception "MissingReferenceException: The Object of type 'Child' has been destroyed but you are still trying to access it" is thrown

Reproducible with: 2019.3.0b1, 2019.3.0f6, 2020.1.0a22
Could not test with: 2017.4.37f1, 2018.4.17f1, 2019.3.0a12 because Configurable Enter Play Mode was introduced in 2019.3 beta

Notes:
1. It only reproduces when the value of the public field is changed of the "Child" Prefab in the Inspector and CTRL + S is pressed while the input box is still selected before entering the Play mode
2. It only reproduces when Domain Reloading is disabled in the Project Settings
3. It reproduces when GetComponent method is used for accessing the Prefab
4. It does not reproduce when the value is changed in the "Parent" Prefab
5. It does not reproduce in the Prefab Mode