During Game my Mac freezes all movement except for chatting

Every once in awhile during a random game:

• Clicking on the mouse doesn't do anything (applies to camera also)
• All keys except for "enter" doesn't do anything either
• I'm unable to leave the game to reset client

The only exception is the enter key, I still have the ability to chat with other player but that's it. The only thing other chat is force power down my mac. This problem has given me a LeaverBuster bans and I can't do anything about it. If you have a solution please reply.