When the application is running, Windows 10 enables "Focus Assist"
I don't know whether this is by design, but when the application is running Windows 10 thinks you are running some form of full screen application / presentation and turns on "Focus Assist" mode. This then prevents any notifications from popping up as they normally would
When you have activated the Windows 10 setting "automatically hide taskbar", even the windows taskbar is behind the active window if you try to activate the taskbar by your mouse-cursor. This should be fixed.
I still have this issue.
So I use the auto-hide taskbar feature and Carnac completely breaks it. I cannot hover over the bottom of the screen anymore to see my taskbar.