Its not a hw issue that they can fix for sure; they will probably just reflash kdz and be done with it.
Issue seems to be caused by VoIP programs somehow. For me the culprit was viber, for ezet skype. No fix, other than flashing a different rom, and hoping the bug doesnt appear again (i had this issue on 4-5 separate roms, including stock, so its not related only to custom roms)
Last edited by Flying_Bear; 13th January 2014 at 02:11 PM.