How to reproduce:

1. Open the attached project and a "test" scene in it.
2. In Hierarchy window under the Canvas element select "scale_tests" game object.
3. Open Animation window and notice that "scale_tests" game object has 18 grandchildren and all of them are named sequential.
4. Select "Image_01" key frame and notice that "Image_12" key frame was selected to.
5. Expand "Image_12" in the Animation window and notice that only key frames on X and Z axis were selected.

Expected behavior: Only one key frame is selected.
Actual behavior: Selecting key frame of one child game object in the timeline also highlights the keys on another child game object in that hierarchy.

Reproducible: 5.2.4f1, 5.3.4f1, 5.3.6f1, 5.4.0f2, 5.5.0a4