Wwise Meter not updating RTPC in UE4

Using UE 4.14.1 & Wwise 2016.2.2

tl;dr An effect works in Wwise Authoring but not in Unreal.

I have two sounds, A and B. Sound A has an instantiated Wwise Meter that sets an RTPC. The RTPC changes the volume of sound B. This works great in Wwise Authoring, but the RTPC doesn’t get updated while in UE4. I’ve connected Wwise to the game while it’s running and verified that the RTPC never changes from the default value.

Is there something I need to enable to make this work? Or does anyone have tips on where to start looking? I’m not sure how to debug this further.