Workspaces not switching automatically
I've seen this intermittently for a few releases now. I fix it by restarting the "Dock" process (which handles Spaces/MissionControl) using this Terminal command:

killall Dock

I don't know how to do that via the regular GUI, sorry. And before you run that command, do killall -s Dock to see the processes which will get killed. If only the one "Dock" process is listed then you're good to go.  Hope this helps!