If you go into creative mode and have a shulker box with items in it, when you go to break it, the shulker box drops and duplicates all items inside of it.
steps for recreation:
1.) get any color shulker box via command or through the creative menu
2.)put items in the shulker box
3.) mine the shulker box in creative
Thank you for your report!
We're actually already tracking this issue in MC-107380, so I resolved and linked this ticket as a duplicate.
However, that ticket has already been resolved. That means that this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
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