UE4 Animation triggered footsteps not responding to RTCP

Question

I have animations in UE4 triggering footsteps using Anim Notify Ak Events attached to the foot bones. I have added AkComponents for each foot to the mesh (as suggested by an AK warning in UE4), and specified the same bones in the Parent Socket setting. The warnings are gone and I can see these AkComponents in the wwise game object profiler.

I am trying to adjust the volume of these footsteps based on the player velocity, so I have a RTPC set up on the animation blueprint for the main character. The problem is the footstep game objects in wwise are not receiving the RTCP value.

If I set up a separate sound on the player blueprint that is just triggered by EventBegin using AkPostEvent, this sound receives the RTPC just fine, so I know I've got the RTPC set correctly.

The question is why don't these footstep AkComponent objects receive the RTPC?