I don't know what causes this problem but i have never had a problem with it on my tour. My friend on the other hand, has the same problem with his storm. His doesn't do it all the time though.
happens to me too but only to a certain friend that is on att but dont sweat it just a bug....what software you running on because it only started happening to me when i switched to 5.0.0.230 never with 4.7