Benjamin McGillicudy

To add to Rat Dog's comment above- If you go and stand in one of those dark cave, log out, and then log back in- the cave within chunk you are in will now be lit up.

This lags my game more than a few seconds.. I have a large biomes world, and testing the locate command lags to the point of the game freezing- I am simply forced to force quit the game.

I have had this bug occur today whilst going through a cave. I never even saw a drowned mob nearby, and I was at diamond level with no oceans nearby. Yet my crash report reveals the same thing as everyone else here- a Drowned mob.
My world seemed to be corrupt... But I made a few copies in the saves folder, and kept trying to open them. Eventually I got back into my world, ran away from the effected area, and then happened to crash again minutes after.
I have reloaded a world that is now working, but I am not moving until this is fixed! Or, perhaps I should play on peaceful for now...

The weird and important thing to note is that I have created a drowned mob grinder from a zombie spawner far away from where I crashed in this world... And I spent a good hour or so converting zombies to drowned and killing them without a crash happening!
Perhaps... As I think the crash report is suggesting... This has something to do with them swimming, as my farm did not allow them to 'swim around'.