If you initiate sitting from a slab or any block that is less than a full block (path blocks, trap doors, chests, etc) when you stand, it appears it teleports you inside the partial block, instead of on top of it. If there's no blocks under the partial block, you will fall through it.
If you initiate sitting from a slab or any block that is less than a full block (path blocks, trap doors, chests, etc) when you stand, it appears it teleports you inside the partial block, instead of on top of it. If there's no blocks under the partial block, you will fall through it.