The bug

Shulkers move their heads vertically (up/down) to where the player died. They don't move their heads back to their original rotation after the player died unless the player save and quits the world.

To reproduce

1. Spawn multiple shulkers
2. Die above/below the shulkers in survival
   → The heads of the shulkers are facing upwards/downwards and notice that their heads are stuck to the rotation.