I created a Custom mob spawner using the setblock command, and after it spawned some entities, "Ghost" entities started appearing out of nowhere, these entites cannot be killed by the command /kill @e, and cannot be interacted with in any way

Steps to Reproduce:
1. Create a Superflat world
2. Teleport to (0,0)
3. Use the setblock command to make a Custom spawner, the one I used was:

 /setblock 27 58 4 mob_spawner 0 destroy {MaxSpawnDelay:1,MinSpawnDelay:1,SpawnCount:1,MaxNearbyEntities:1,EntityId:Item,SpawnRange:0,RequiredPlayerRange:32000,SpawnData:{Item:{id:264,Count:1},Pos:[27.5,57.2,4.5]}}

4. Make the Spawner spawn some entities
5. Notice how out of nowhere "Ghost" entities start to appear