THX Spatial - Some Games (PC Gamepass?) not showing in "application mixer'

As the title states, I'm really trying to get a certain game (Snowrunner) from PC Gamepass to show up in the Application mixer of the THX Spatial app. I have Blackshark v2 (no usb audio card), but it doesn't seem to want to show up at all. Other games, such as Outriders and Fortnite do, but not Snowrunner. I noticed with many other Gamepass games the "Xbox PC App" shows up in the Mixer, but not Snowrunner. Anyone have any tips? Thanks.