This is not new to iOS 8.3 beta 2. I've had this happen quite a lot in the public builds of iOS 8, it's happened in the beta cycle for iOS 8.0 beta, it even happened way back in the iOS 7.0 and 7.1 betas I believe. Not sure what it is, but ever since the iOS 7 redesign the keyboard has been having issues with coming up in the right orientation. Don't worry, it will most likely be ironed out before the public version of 8.3 drops, and iOS 9 may be a major bug fix and performance update, too. Until then, just close the app from the App Switcher and start it up again.