This is weird. Both my wife and I have Thunderbolts. Occasionally, when we try to make a call from the Thunderbolt to another phone, the calling phone rings but the other phone doesn't, so the caller is sent to voicemail. If you look at the receiving phone, it shows no missed called. This has happened several times, me using my Thunderbolt to call my wife on her Thunderbolt, my wife using her Thunderbolt to call me on my Thunderbolt, and both of us calling from our respective Thunderbolts to my daughter, who is using an Incredible 1. This has also happened a couple of other times when I tried to call someone else and they didn't answer and it went to their voicemail. When I spoke to them later, they said that their phone never rang. This issue seems to have begun after I had installed the update. Have anyone else noticed this?