Items fall into opening shulker

The bug

Items fall into opening shulker.
Also affects when it riding on an entity.

⚠️ After version 26.3 Snapshot 1, this will only affect multiplayer mode or LAN.

Steps to reproduce

1. Make the World Open to LAN.

2. Summon a shulker:
   /summon minecraft:shulker ~ ~ ~ {Peek:0b,NoAI:1}

3. Drop the item on top of it.

4. Use the following command:
   /data merge entity @e[type=minecraft:shulker,limit=1,distance=..5] {Peek:30b}

5. Found items repeatedly kept falling into the shulker.