Just before the update to 1.8.1 there was an issue were when i would sleep all of a sudden I would be about 4 or 5 blocks in the air.  I thought little of it until today when i did a save and quit in a base i was building, and then reloaded the saved game.  Once the game loaded i thought it was doing the usual load player and compile world, but instead i was transported into the sky and dropped to my death in a random location.