Muting the top most track row is muting all track rows

The workflow above is generally used to pull out key poses from a mocap performance.

It works on 5.0.

It can be simplified for QC into this:

1. add some animation keys to your rigged character in Sequencer.
2. create an animation layer (additive or absolute)
3. add animation to the anim layer
4. mute the top original layer

No animation will paly despite there is an unmuted layer still active.
Looks like that muting the top anim layer mutes everything below as well.

Simple repro:

1. Add a static mesh to a level sequence
2. Add an additive transform section
3. Right click on the first Transform Track and mute it

RESULT: Both transform track rows are muted.

EXPECTED: Only the track row that you clicked on should be muted.

Original repro:

1. Create a Level Sequence.
2. Add a skeletal mesh (Quinn or Mannequinn)
3. Attach an animation clip to the SKM (i.e. Run)
4. Bake the animation to Control Rig
5. Add an absolute animation layer to the control rig 
6. mute the absolute layer
7. add keys on all ctrls to the muted animation layer on random frames
8. mute the top layer (with the original run)
9. unmute the absolute layer

At this point no animation will show on the rig, despite the fact the the absolute layer does have animated keys in it.