How to reproduce:
1. Create a new project
2. Enter the Scene View and enable the Effects button
3. Enter the Play Mode (it can be exited immediately after)

Expected result: The Effects button is still enabled (remains unchanged)
Actual result: The Effects button is disabled

Reproducible with: 2020.1.0a24, 2020.1.0b1
Not reproducible with: 2017.4.37f1, 2018.4.19f1, 2019.3.5f1, 2020.1.0a23, 2020.2.0a3

Notes:
1. The attached image shows the Effects button location (Scene view control bar is slightly different in other Unity versions)
2. If the Effects button is disabled before entering Play Mode, it continues to stay disabled as it would be expected
3. The Effects menu has options to enable or disable rendering effects (Skybox, Fog, Flares...) but whether these are on or off the issue still occurs.
4. Upon creating the project in the versions that the bug reproduces, the Effects button is already disabled. While in the versions that the bug does not reproduce the Effects button is initially enabled.