Black-Screen upon Game Exit on OS/X when using a Managed Account

When using a "managed" login/account on OS/X, every time the game is exited, the machine "black screens". The only way to resolve this has been to SSH from another device and kill -9 the account's login process [i.e., killing the minecraft process is not sufficient, the user's login must be killed].
This happens 100% of the time, when using a managed account to play the game. Changing the account from Managed to Standard resolved the issue.