Shulkers can "magically" sense the player's movement when closed

The Bug:

Shulkers can detect a player's movements even if their shell is closed. This applies to all game modes except spectator.

Steps to Reproduce:

1. Summon a shulker.
2. Press F3 + B to enable hitboxes.
3. Orbit the shulker with a 1-3 block radius.
   → The shulker's blue line will eventually start to follow you if you walk close to it.

For survival and adventure mode, you can try to build an enclosed area and use regeneration to avoid being killed.

/effect give @s minecraft:regeneration infinite 99 true