Float Particle Parameter for Point Gravity Strength Raw does not work

The Distribution Float Particle Parameter setting for Point Gravity Source "Strength Raw" doesn't accept values being passed into it from Blueprint.

1. Open attached project
2. Select blueprint in the center of the scene that contains the particle system
3. Change the exposed parameters "Radius" and "Gravity" while in the view port so you can view the changes (Radius is set up to compare a particle parameter that works vs the one that doesn't)

RESULT
Sphere radius changes however the Point gravity strength doesn't

EXPECTED
Both Sphere Radius and Point gravity strength change