Editor crashes on resetting Virtual Camera prefab.

Steps to repro:
1. Create a new Project.
2. Windows > Package Manager > Cinemachine > Install.
3. Create a Virtual Camera from Cinemachine menu.
4. Create prefab of Virtual Camera(CM vcam1).
5. Reset using burger button.

Actual Result:
Editor crashes on resetting Virtual Camera prefab.

Expected Result:
Virtual Camera prefab properties should be reset.

Reproducible in:
-2020.1.0a21 with 2.5.0.
-2019.3.0f6(27ab2135bccf) with 2.5.0, 2.4.0, 2.3.4, 2.3.3.
-2019.2.1f1 with Package Version: 2.5.0, 2.4.0, 2.3.4, 2.3.3

-Reproducible in 2019.2.0a13 with Package Version: 2.5.0, 2.4.0, 2.3.4.
-Working Fine in 2019.2.0a12 with Package Version: 2.4.0, 2.3.4.

Environment:
Occurring on Windows & Mac.