shulkers fall to the bottom of the world and die when passing through the End portal due to shulker-specific movement and portal coordinate bugs.

Bug Description:
When a shulker passes through the End portal from the End to the Overworld, it often spawns at abnormally low Y coordinates near the bottom of the world (around Y = -64 to -66), causing it to fall and die. This issue occurs only with shulkers; other entities pass through normally.

Steps to Reproduce:

1. Move a shulker through an End portal from the End dimension to the Overworld.

2. Observe the shulker’s spawn location and behavior in the Overworld.

Expected Behavior:
The shulker should spawn at a valid location in the Overworld, such as near the world spawn point or a safe coordinate, without falling through the world.

Actual Behavior:
The shulker spawns near the bottom of the world and falls to its death. Other entities teleport through the portal and spawn normally.