You have created a "saved settings template" using the SlingStudio Console Save Project as Default feature. But now audio settings, especially muting certain sources, don't work correctly.
This can happen if, when you created a settings template using the Save Project as Default feature, there was a video clip playing in the Program window. Doing this, then creating project files via the Save Project as Default feature, can set up a situation in which SlingStudio Console audio settings don't work improperly, especially when trying to mute video sources.
Use the Save Project as Template feature within SlingStudio Console to create a new settings template. But this time, be sure not to have any video clips running in the Program window.