How to reproduce:
1. Open the project “IN_31226”
2. Open “SampleScene” Scene
3. Select “Cube” GameObject
4. In the Inspector right-click on the “Event System” component → Properties
5. Enter the Play Mode
6. In the Properties window disable and enable “Send Navigation Events”

Expected result: no errors in the Console
Actual result: error “MissingReferenceException” in the Console

Reproducible with: 2021.1.0a9, 2021.3.19f1, 2022.1.0a5
Not reproducible with: 2020.3.44f1, 2021.1.0a8, 2022.1.0a6, 2022.2.7f1, 2023.1.0b4, 2023.2.0a2
Fixed in: 2022.1.0a6

Reproducible on: Windows 10 Pro

Note: reproducible on a new project