Hi I am seeing this strange issue after upgrading to 2.6.3. If I call this phone, I can hear it ringing but dont see the phone ringing. It could be an att issue and exchange may be giving ringtone back. But I am pretty sure it's handset issue as it happens a lot only after upgrade. I've another iPhone with att and I don't see any issues there. Has anyone seen this issue? Would really appreciate any inputs on this. I miss 7 out of 10 callls Thanks.