Steps to reproduce:

1) Download attached project 'AnimatorControllerBundleCrash.zip' and open in Unity
2) Open 'Main' Scene and press Play
----Observe crash

Reproduced with:
5.6.0b10, 5.6.0p4, 2017.1.0b4

Not reproduced with:
5.5.3p3, 5.6.0b9

Regression from:
5.6.0b10

Note: full Stack Trace attached

========== OUTPUTING STACK TRACE ==================

0x000000014083AADF (Unity) AnimationClip::BuildMecanimDataMainThread
0x000000014083AFF4 (Unity) UnityEngine::Animation::CreateAnimationSetBindings
0x000000014083B908 (Unity) AnimatorController::AwakeFromLoad
0x00000001410753EE (Unity) AwakeFromLoadQueue::PersistentManagerAwakeSingleObject
0x0000000141075A4C (Unity) PersistentManager::IntegrateObjectAndUnlockIntegrationMutexInternal
0x000000014107FF73 (Unity) PersistentManager::ReadObject
0x00000001407B8C97 (Unity) PPtr<RuntimeAnimatorController>::operator RuntimeAnimatorController * __ptr64
0x000000014086F81E (Unity) AnimatorOverrideController::AwakeFromLoad
0x00000001410753EE (Unity) AwakeFromLoadQueue::PersistentManagerAwakeSingleObject
0x0000000141075A4C (Unity) PersistentManager::IntegrateObjectAndUnlockIntegrationMutexInternal
0x0000000141019391 (Unity) TimeSliceAwakeFromLoadQueue::IntegrateTimeSliced
0x00000001410195FD (Unity) LoadOperation::IntegrateTimeSliced