I'm really sorry about this! I didn't know it was even possible to make the keyboard visible on the app's home screen! Definitely not the intended behavior.
Hmmm... after a couple of minutes of trying to provoke this, I'm failing utterly; backing out of any given screen clears the keyboard. I think something out of the ordinary is definitely going on here - this may be one of those things that's hard to provoke, but once it happens, it gets stuck that way.
Can you email the
support ninjas so we can investigate this with you? We'd love to figure out what's going on.