If you’re a Windows Phone 7 user and you’re currently experiencing issues with the Halo Waypoint app, please clear your cache, as we recently made some changes that may cause instability until that action is taken. Thanks!
I had issues with the iOS app too, fortunately i only had to sign in again.
Although not a bug, apparently the Windows Phone 7 App has a Halo 4 section, will the iOS receive similar treatment soon?