Niagara's submix isn't getting any data from sound waves?

I’m getting a strange issue.

I have a sound wave asset (.wav) and I set the Base submix to Submix1.

Submix1 is just a new submix with no other inputs. It’s going straight to the master.

In Niagara’s Scratch Module, I am using Audio Spectrum and setting the Submix to Submix1.

I drag and drop the sound wave into the level.

The Scratch Module is just using an Audio Spectrum to increase the velocity of the particles.

Now here’s the issue. When I hit “PLAY” on top to play the level, I hear the sound but the Niagara FX isn’t reacting to the sound at all during gameplay. However, if I exit the play then press play on the sound wave from the content browser, the Niagara FX will react.

Any insight into what may be happening here? Thanks!