This is a pretty frustrating bug. Using Unity 4.7.2 and NGUI 3.10.2 I place a UISprite in the top left of the screen. Then using the sprites anchoring dropdown, choose unified. Before I can do anything else the sprite jumps off screen somewhere random and I have to use the anchor variables to bring it back on screen. It used to be the sprite would stay where it was when you enabled the anchor.