Put the summary of the bug you're having here

What I expected to happen was...:
When you went to the End City, you had three objectives, kill shulkers, take the elytras and the dragon head, but when you are going to kill shulkers, you have to wait they open their box, because their box decreases the damage we did to them.

What actually happened was...:
But when a shulker stay closed, and tried to attack, they could stay closed while they are sending many proyectiles to the player, and it's annoying because the arrows don't work and attack with a sword or axe take a lot of time.

Steps to Reproduce:
1. Search an End City.
2. Go to the large pillars.
3. Attack and in a moment, Some shulkers are going to attack closed.