Have you guys ever connected your phone to Bluetooth device such as external speaker, hands free etc? I have this problem too, and it seems everything started when I connected my phone to my mini boombox (using Bluetooth). Somehow the problems gone, I don't know how. But I remember I've restore my nandroid backup several times, not because of this issue, but I've crashed my camera after trying Xperia z2 camera app and libraries.
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