Duplicate?

I used to do a duplication glitch by filling my backpack with the desired items I wanted to duplicate.
Then find a death zombie and click on ''gear'' then open up your backpack and then put the items in the zombie and then put it back in your inventory.
But I noticed it doesn't work anymore.
Does anyone know about this?

I believe this was disabled with the last update. I might be wrong though. Are you doing it on high population servers? I know it was related to the amount of time the server took to report to the hive. Which is why it worked on high pop servers.