Reproduction steps:
1. Open attached project
2. Open the "test" scene
3. Drag the "bug" animation controller onto the "bugObject" animator and save the scene
4. Re-open the scene
5. Notice that the "bugObject" has the old animation controller (HumanMaleHumakti)

Actual result: The new animation controller isn't saved onto the "bugobject" gameObject

Expected result: The new animation controller should be save onto the "bugObject" gameObject

Workaround: After adding the new animator controller change the gameObjects name and then save.

Regression introduced in: 5.3