I'm having problems similar to this question, so I know how to make the text reappear after it disappears: just type "stty echo" or "reset." But how do I prevent it from happening in the first place? Why does it happen?
Update 10/24/15: I figured out the issue. Whenever I was using binding.pry and exited it with CTRL-C, the problem occurred. Now I exit binding.pry the "legal" way, by typing "exit!", and I haven't had invisible text since then.