First of all, thank you for the macOS support!
This happens with the macOS client but doesn't happen with the Geforce Now app.
When playing the Apple Music app in the background, anytime there is a sound effect from the game, the music lowers the volume and returns. This isn't happening with GFN or other native macOS games.
Macbook Air M2 (8 gig RAM / 512 SSD) Sonoma 14.5