First, make sure you added the Sound Alerts Browser Source to your OBS. Right-Click and hit "Properties". Check that "Control audio via OBS" is enabled. Open the advanced audio properties and set the Sound Alerts Browser Source to "Monitor & Output".
Now uncheck all the tracks for Sound Alerts and give it a separate track from the Desktop Audio track.
Solution Summary: Ensure the Sound Alerts and Desktop Audio tracks are not check-marked on the same track. Uncheck all tracks and apply only one checkmark to Desktop Audio and one checkmark to Sound Alerts, ensuring they don't share the same track.
If you have any questions left, please get in touch with us and visit our Sound Alerts Discord Server.