I'm not sure how to explain it, I think its a certain range of chunks that make the game crash and not load properly. I'm assuming its because there's a significant amount of chests, but other areas seem fine. The chunks never crashed until this most recent patch.
Oceanic mobs can no longer spawn in bubble columns (magma blocks and soulsand).
You're in a version where there's no dedicated servers so you can't play on them until you either leave the beta or the full release comes out