How to reproduce:
1. Open the user attached "DebugTest.zip" project
2. Enter the "SampleScene" Scene
3. Open the "Test.cs" Script with Rider
4. Add a Breakpoint to the line containing the Debug.Log command
5. Return to the Editor and turn on Debug Mode
6. Press Play
7. Return to the IDE and Attach the Unity Process (Run -> Attach to Unity Process)
8. Stop Debugging in the IDE and return to the Editor
9. Exit Play Mode
10. Disable and re-enable the Debug Mode
11. Return to your IDE and re-attach the Unity Process

Expected result: The Unity Process is attached successfully
Actual result: "Unable to connect to Unity" is thrown in the IDE

Reproducible with: 3.0.6, 3.0.12 (2021.2.0a18, 2021.2.13f1, 2022.1.0b9, 2022.2.0a5)
Not reproducible with: 3.0.5, 3.0.6, 3.0.12 (2020.3.30f1, 2021.2.0a15)
Couldn't test with: 2019.4.36f1 (No Debug button), 2021.2.0a16, 2021.2.0a17 (Debug button does not open)

Note:
- Reproducible with Visual Studio and Rider
- Visual Studio Code throws "No Unity Process Found" (Cannot test)
- Reproducible with a new project