Fishing rod bobbers do not deflect off of closed shulkers like other projectiles

Despite closed shulkers deflecting projectiles like tridents, arrows, and other projectiles (currently blocked by MC-148451), fishing rod bobbers can still attach to them. This is unusual when compared to breeze mobs which also deflect projectiles, and endermen which projectiles cannot hit (though, the fishing rod bobber can connect because of MC-96092)

Steps to Reproduce:

1. Spawn a shulker with no AI, closed:

   /summon minecraft:shulker ~ ~ ~ {NoAI:1b}

2. Use a fishing rod on it

Observed Behavior:

The rod's bobber attaches to the shulker.

Expected Behavior:

The bobber would either deflect off, or just land on the closed shulker until it opens.

Screenshots/Videos: