Reproduction steps:

1. Open "MinimalRepro" project
2. Select "GameObject" in the Hierarchy window
3. Drag "Main Camera" into the Timeline window -> "Add Cinemachine Track"
4. Drag "CM vcam1" into the "Cinemachine Track"
5. See a Warning in the Console window: "No script asset for CinemachineShot. Check that the definition is in a file of the same name and that it compiles properly."
6. Reload the project

Expected Result: The Cinemachine Track works after project reload and no errors appear
Actual Result: "Track cannot be loaded."

Fixed in: 2019.3.0a7

Reproduced with: 2019.1.0a13, 2019.1.0a12
Did not reproduce on: 2019.1.0a11 (No Timeline Window), 2019.1.0a10, 2019.1.0a6, 2019.1.0a1, 2018.3.2f1, 2018.3.0a1, 2017.4.18f1, 2017.3.0a1