Hold phone in portrait mode. In mail, open a message with a PDF attachment. Touch the attachment to view it. Put phone in landscape mode. Touch "message" at the top left to go back. Put phone in portrait mode. Screen does the spinny transition thing nonsensically. Or am I crazy? In playing with this I've also managed to get it to confuse portrait and landscape, leaving a giant black box at the bottom of the screen, but I can't seem to reproduce it yet.