If the Teacher Tracker software is not switching, check:
that the tracking feature is enabled(Teacher Tracker > Info) and that both cameras are LIVE:
Check the light conditions (If the light in the room is too bright or too dark tracking will not work)
that the Audience exclusion zone (Tracker > Audience) has not been set above the upper body of the teacher
if on stage there would be any object that would reflect the speaker or looking like a person that would make the software interpret that several people are on stage
The calibration process takes only a few minutes to complete, always re-calibrate the system if you move the cameras to a new location, or when you changed their position within the same classroom.
And finally be aware that the goal of the CamDirector is not to track the teacher as much as possible, but to give a calm and a pleasant to watch video on the output. The system prevents too much switching between cameras during a typical 1,5-hour college lesson.