Sequencer - Particle Material Parameter not working

I’m trying to animate a material parameter of a particle system. The particle is an instanced mesh type, and has a Material Instance with an opacity parameter for fading. I can drill down in sequencer and create a track for that parameter, but it doesn’t do anything.

If I do the same with a static mesh, the parameter works fine. It’s only broken when used in a particle system.

The way I’m setting it up for both is to add the staticMesh or Particle system>Component0>Material Element0>parameterName

This seems like it should work.