I using Unity 4.5. And with Windows build, in my game, when I press back button there is a pause menu in my game. When I press resume in that menu, the state and look of “Resume” button stays like it pressed. I’m using guistyle to define hover state of button. I don’t have this behaviour on any other devices.
Resume toggle Time.timescale, if it helps.
Seems like a bug, I suggest you to submit a bug report.
For solving your problem, you just need to avoid using the hover state, since it’s no needed on mobile devices with touch screen.