1. Import Survival Shooter 5.
2. Open Animator Window.
3. Go to _CompletedAssets -> Animation -> PlayerAnimatorController.
4. In Animator Window delete Move state.

Alternative reproduction steps:
1. Create new project
2. Download & Import Mecanim Example Scenes from Asset Store
3. Select any animation in the Controlls folder
4. Select first state (orange)
5. Delete the state

Actual result: All graph in corrupts the window and graphs. Multiple errors in console:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Graphs.AnimationStateMachine.Graph.CreateAnyStateEdges (UnityEditor.Animations.AnimatorStateTransition transition) .......

The anim.controller file get's corrupted permanently.

Reproduces in 5.2.2p1, 5.3.x, 5.4.a2.
Win 8.1 / Mac 10.9

Expected result: No errors in log, state is deleted, all rest graph stays in Animator Window.