Repro steps:
1. Open user attached project
2. Select "CharlieRunAni" in the Project Window
3. Open it in the Animation Window
4. In the Hierarchy select "Body" and rename either of its child GameObjects

Expected: The corresponding property in the Animation window is renamed
Actual: The property isn't renamed and the reference is lost. The tooltip says "The GameObject or Component is missing"

Reproducible with: 2017.1.5f1, 2017.2.3p2, 2017.4.8f1, 2018.1.9f1, 2018.2.1f1, 2018.3.0a5

Notes:
- Works when renaming the root GameObject

By design: Because a clip can be played on any number of GameObjects changing all clips that were made on a GameObject every time the name is changed would potentially break the animation clip for every other GameObject that the clip is used for.