1. Open QA attached project "fbxPrefab"
2. Open scene "test"
3. Add "Rock" to the Hierarchy Window
4. Add some components to the GameObject "Rock"
5. Click Revert
6. Observe the console and the Inspector Window

Expected: changes made to the GameObject are reverted.
Actual: added components and other changes aren't reverted and a NullReference Exception is thrown.

Reproducible with: 2017.2.0f3, 2017.3.1f1, 2017.4.0f1, 2018.1.0b13, 2018.2.0a7
Not reproducible with: 2017.2.0f2, 2017.3.0a7
Regressed in: 2017.2.0f3

Workaround: drag the GameObject from Hierarchy Window to Project Window (as when creating a prefab) then making changes to the same GameObject and reverting them works as expected.

Fixed in 2018.2.0a9.