Some applications do not like to follow Windows's "App volume & device preferences" routing assignments. There is an application that we previously recommended (EarTrumpet) that made those assignments "stickier" so that they actually hold their assignments.
However in app version 1.0.273 we implemented a drag and drop system that performs app assignments to devices the same way as EarTrumpet, meaning you no longer need EarTrumpet installed and can do almost all application assignments from within the BEACN app.
"System Sounds" is controlled by Windows and is not able to be routed anywhere besides the set default device.
Though in some instances routing through EarTrumpet will not work at all, this is usually because the application's design does not allow for routing to other devices. This will mostly affect older indie games, but can include games like GTA 5 and Escape from Tarkov.
Some games and apps like Discord have in-app audio settings that override the windows assignments. In those cases you must set the audio in-app (if applicable). Otherwise you must use the method mentioned below.
When using the drag and drop feature, if either of the 2 above conditions are true you will see the application bounce back to the previous device it was assigned to in-app. In the future we plan to make a notification or popup appear to inform you that this is the case and that the app cannot be routed that way.
This is also the case with our drag and drop feature—any application that wouldn't stick with EarTrumpet will not stick via the BEACN App
The alternative we suggest for this is to set your default device in Windows to the "Game" device instead of "System", and then route apps that you want on your System knob to the "System" device.