I think this may be a streaming API issue based on this article http://thenextweb.com/twitter/2012/09/27/twitter-iphone-displaying-mentions/ but I’m not sure.
I have a service that @mentions users with a daily information message. The majority of the users receive this is an alert in the Connect tab or similar. However a minority don’t. The message is definitely sent and can be seen on the website, example:
Would welcome any thoughts on where I can look next.