Shulker Boxes and End Chest Disappearing

I placed down Shulker boxes and an end chest about 10 blocks below the ender dragon in the end. With about a three or four block thick roof above me. I came back a minute later and all my valuables that were in the Skulker boxes were gone because both the end chest and the Shulker boxes has disappeared. 

By the way the version I said I was in could be wrong I don't really know for sure what version Im in.