This is only an iOS 8 problem, the keyboard displays correctly in iOS 7 with device orientation change. My application supports both portrait and landscape orientation and u
It is is not a bug of iOS8 or iPhone 6. It is problem of the correct migration of old projects to xCode6.
You simply need to add Launch screen interface file base name key to Info.plist file.
Launch screen interface file base name
Info.plist
Detailed explanation of this case you can find here.