Yes, it is normal. I think it appears like that either because it's a new notification or it's the only notification or even both. I've seen it like that before, never really thought it was out of the ordinary.
Now I know HOW this happens.
As your screen is locked when you received the notification, it only shows you the most recent notification until you ignore it an let the screen turn off or you turn of the screen or you pull the notification centre down.
When I was running the iOS 5 beta, the first beta only displayed the notifications in the little bars, they changed it in the 2nd beta to do the more traditional notification (in black this time) for the most recent notification and then the next time you look at your lockscreen, the little bars again.
I would like for two things:
1. To turn off the big one and always have the little bars
2. Keep the notifications on the lock screen till they're cleared just like notification center... Hell, let me pull down notification center on the lockscreen. Then I get weather on the lockscreen too!