This issue is present since the first versions of InputDirecor for the last years.
I have reported it 2 years ago already, so it is really annoying the problem is still not fixed with 2.0.1.
I have this issue since I use InputDirector from the beginning.
The only workaround for this is to bind a key to move the mouse back to a computer, i have set F6 to move cursor back to Master.
It randomly happens all the time, that the mouse cursor is gone when you switch between master and client. Happens every 5 minutes or so.
Fix this already.