Help notification sound issue after ics update galaxy s two

[mrwatknz]

Me to many bugs after ics well i was told by Samsung and att we can go back. To gingerbread .I am having trouble with notification sound stopping daily between 3 and 5 its weird i on third phone from att same issue. A reboot fixes problem till next day at same time and am not doing anything to phone between this time. Really makes me mad my phone was great until ics update and nobody can figure out why . I just turned off auto sync thinking this might effect. Its got to be something the phone is doing on its on. Like i say third phone and tried all stock with no added apps but same issue. Hoping to post on her to get help