Global High Scores Not Always Viewable

[Coffee_n_Donuts]

I know other people are having this problem but it still hasn't been addressed. You cannot always view the Global High Scores, sometimes you can and sometimes you can't. I know it's linked to Openfient but why does it sometimes not log in? I have iPad 2 3G and Wifi so I always have a connection but it doesn't always log you in. Game Centre logs in straight away but not OF, why?

Sometimes you load up the game, check out the high scores, play a game, and then when you try to check the scores again you can't. It's just very frustrating.

Any idea what the cause of this is Zen?