Entities will not stay mounted on shulker when they teleport. This is unlike when an enderman teleports, where the player (or any entity) will stay mounted on it.

Steps to Reproduce:

1. Summon/spawn a shulker
2. Ride it

   /ride @p mount @e[type=minecraft:shulker,sort=nearest,limit=1]
   

3. Place use a water bucket nex to the shulker, forcing it to teleport

Observed Behavior:

The shulker teleports, and the player is not brought with the shulker.

Expected Result:

The player would continue to ride the shulker, just like when they ride an enderman when it teleports.

Screenshots/Videos:

ShulkerTeleport.mp4

Notes:

1. This behavior was observed when trying to ride a shulker through a portal block. Because the shulker needs to instantly teleport to a valid location when traveling through a portal, the player will stop riding it.
2. May relate to MC-44514 MC-102608 MC-97513