Audio effect changes with exposed parameters not working on Android?

I've just run into a weird limitation when using exposed parameters on audio effects on Android.

I know the script is working, because I have it hooked to canvas sliders for testing in the editor and it works just fine. Slider changes the intensity of the exposed parameter. But not on Android, the Oculus Quest to be precise.

I also know the controller on the Quest sends correct signals, as I control a visual effect with the same method and that does work no problem.

Strangely, if I pre-set the intensity of the audio effect in the editor, the effect does work on the Quest, so it is capable of running audio effects.

Am I missing something, or is there really some weird limit on changing exposed parameters in real time on Android?