Are you using the CNN or the Nokia one. I have found that the Nokia tends to not update. I have the CNN one installed and it is updating normally. One thing you should check is if you have it enabled to run on the background.
I had that same issue too. I couldn't get it to work after deleting and reinstalling so I decided to not have a LiveTile for ESPN. Surprisingly enough my battery performance increased by a lot when I removed ESPN from running in the background.
Oh noooo, sorry to hear folks are not getting timely updates on CNN/ESPN apps. I rely on both and am using an iphone 4 till my L920 arrives.... What have i got myself into :-(
Holy Christ. During the election this app drove me to the brink with all the alerts. FWIW I have the Nokia version of the app installed, not the official one.