Windows 7, 64bit
This strange thing generated in my world, i think it might be caused by the deep ocean and roofed forest biome have a way to high difference in height. See the pictures, it is a huge cliff(not intended i am quite sure of that). as you can see i put some glowstone on it to make it visible a little better.
i paused the game at this spot, went away for about 20 min, when i came back, minecraft suddenly sped up and it became night and day within a matter of secconds. (like the pause did pause my world, but not the time within the world)[seccond bug]