Huge bug on survival single player, furnaces and chests bug so you can't use them! I don't know why, but reconnecting doesn't work, when you destroy them, you only get the chest or furnace you destroyed, as if it's became an undefined block... often happens after you mine or fight, while I'm talking about survival, I should point out you get about 20 fps now :/ you don't WANT to play with such a low frame rate, it drops from 1 to 30 and is very unstable unless you are still.
One more pretty big bug is water, it doesn't flow properly, sometimes there's still water when you come to acave that should have water flowing down into it from the ocean... Another problem is, you can pick water up from the sea, BUT YOU CAN'T DROP IT BACK IN! So if you have a current of water you must place the water above the current, then pick it up again to stop it.
I've noticed the water glitches too.