Prefabs limitation ?

I reached this error while creating a prefab.

Out of file ID space for this class.
UnityEditor.PrefabUtility:ReplacePrefab(GameObject, Object, ReplacePrefabOptions)

Is there a known limitation ? I try to create a prefab with a huge number of gameObjects.

I’ve encountered this error yesterday on Unity 5.2.2p2, but it wasn’t related to prefabs from my end.

I have an Animator Controller with multiple layers, and I copied a relatively large StateMachine from one layer to the other. After about ~30 minutes of waiting, the copy operation was ready and the ‘Out of file ID space for this class’ was shown ~1500 times in the console.

Has anyone else encountered this? I’m now on Unity 5.3.1p1 and the problem is still happening when I copy a StateMachine from one layer to the other.

Still happening in Unity 5.3.5p3.