I don't think those things has ever happens to me on my iP4 on 5.0.1 and my iPT4 5.0.1.
But I'm not really not it that much. My girlfriend is on it all the time ony iPT4 and she said she has never seen such things.
Perhaps delete the app, and reinstall it from the AppStore. Not from iTunes.
Actually installing apps from the AppStore instead of iTunes maks the entire device generally function much more smoothly. Tho I think I'm going off topic.