Reproduction steps:
1. Open "Test002" project
2. Play "NewScene"
3. Press "Return"
Notice: The "Avatar"'s hand "Right Hand" (in hierarchy under "Right Sleeve") is gone. It cannot be found even in Scene View

Console:
Quaternion To Matrix conversion failed because input Quaternion is invalid {nan, nan, nan, nan} l=nan
Converting invalid MinMaxAABB
Invalid AABB result
Invalid AABB a
IsFinite(outDistanceForSort)
IsFinite(outDistanceAlongView)

4. Press "Return" again
Notice: The "Right Hand" is back to its place

- Playing animation in the Animation window does not throw an error and animation works as expected

Expected: After pressing "Return" Hand waves/moves
Actual: Hand disappears and throws an AABB error

Reproduced on versions: Unity 5.3.3f1, 5.3.4p6, 5.4.0b18 (does not throw an error, but hand still disappears)