Looks like a software bug and it's going to be fixed in iOS 6.0.1
http://bgr.com/2012/10/22/apple-starts-testing-ios-6-0-1-for-release-in-coming-w eeks-ios-6-1-to-come-after-holidays/
Lets hope above is true and iOS 6.0.1 will fix our problem.
we have a general list of what the first iOS 6 update will entail. iOS 6.0.1 should fix the horizontal lines bug on the screen when the keyboard or app folder is open, and it will also fix a problem with the camera’s flash not going off. In addition, the new software will improve Wi-Fi support, fix cellular data not working in some cases, add a consolidated cellular data switch for iTunes Match, fix a bug that allowed access to Passbook pass details from the lock screen, and also finally fix the bug that caused Exchange meetings to be unexpectedly cancelled for the entire calendar invite group