Sculk cannot replace tuff, smooth basalt, calcite and dripstone block

deepslate doesn't start to generate at y=0

magma blocks can generate in ocean monuments

Grass and dirt generate underground in amplified worlds

Boats that hit the edge of soul soil turn into planks and sticks

Invisible mobs will attack and kill you.

Placing signs can remove blocks

floating point precision affects world rendering.

Build limit in Nether is at y=128

Villagers randomly despawn on Pocket Edition