Switching from 2D to 3D while navigating using arrow keys breaks the navigation tool and makes the scene camera go in the direction it was moving in, in 2D view.
Refer to the attached Video.

Steps to Reproduce:
1. Create a New Project (3D Template)
2. Switch to 2D View
3. While Navigating with Arrow Key, Switch back to 3D view
4. Navigate in 3D view with Arrow Keys/Just press Right-click (To Enter Flythrough Mode)

Actual Result:
Navigation only occurs in the direction it was moving in, in 2D View

Expected Result:
Navigation direction in 3D view should depend on the current Arrow key input

Note:
1. Entering Flythrough mode(Right-click + WASD) also doesn't work till Q or E is used to move up or down.
2. Unable to test on versions 2018.2.0a6-8 and 2018.2.0b1-2 due to this issue https://fogbugz.unity3d.com/f/cases/1022564/

Occurring on:
2020.2.0a5, 2020.1.0b4, 2019.3.7f1, 2018.2.0b3

Working Fine on:
2018.2.0a5, 2018.1.9f2

Environment:
Windows 10 and macOS 10.14

License type: Pro