Shulker shoots after dead

Summary: After getting shulkers to fight eachother, a "phantom shulker" or something similar is created, where it is unkillable, and invisible or maybe just not there, but the levitation orbs keep firing.

I put a bunch of shulkers in an endstone building as kind of a dungeon, and was going to fight through it while trying not to get levitated.

When I went in then I was unprepared and died, but when I came back with weapons and armor, then I noticed the shulkers were attacking eachother. some of them did a sort of teleporting thing and got sideways, but the crazy thing that I think Is a bug is that after I cleared out all the shulkers from the area, the levitation orb things kept shooting, so I checked and they were appearing in midair. It wasn't an invisible shulker as there were no particle effects and I didn't use any potions, and the shulker wasn't even there as I couldn't hurt it or stop the orbs from coming out of this phantom shulker.

EDIT: After I died a few more times, then the shulker magically reappeared where his ghost self had been.

Steps to Reproduce:
1. get a lot of shulkers in a small area
2. fight them so that levitation orbs come out
3. get the orbs to hit the other shulkers so they all fight eachother