Shluker problem 20w51a

Fake shulkers
In 10. January/2021 when I played 20w51a I killed Ender Dragon and went to end islands. There I was looking for End City and i found it. There starts the problem. When I killed fifth shulker I found out that then are not droping any shulker shells. I just said to my self that this is just bad luck but when i killed other shulkers it was confirmed. I tried it also in my other creative worlds and there they were droping so I tried to find out where is the problem and why is that happening.. I found out that when you are in hard difficulty you have a little chance that you find fake end city. How do I mean fake end city? I mean it like you hear. Every entity is fake and drops nothing.