Items vanishing/duplicating if you travel through a nether portal right after placing/ removing items from the chest

First place items into a chest then quickly jump through a nether portal 

next travel awhile through the nether and go through another portal, wait for awhile in the over world then go back through the nether to the original portal and then go through it.

if you have done it right and auto save hasn’t caused chaos the items you placed in the chest should be gone. And also not in your inventory. Here is a clip of me reproducing it. I have also been able to duplicate items using this method by taking items out the chest then when I come back they are still there and in my inventory.

https://drive.google.com/file/d/1bADfCbMUBqtwyHtyneVcd6jbRalZ5vKe/view?usp=drivesdk