Duping

Put the summary of the bug you're having here

What I expected to happen was...:
I thought that by updating my survival world everything would appear the same

What actually happened was...:
A shulker box that got left on the floor was duplicated along with all of the items inside. They were very valuable, such as elytras and fully enchanted armour,.

Steps to Reproduce:
1.  Leave all valuable items in a shulker box

2. leave 

3. update to 1.14

4. come back with duplicated items