So I was playing minecraft, just doing my thing, going to my near by stronghold for end stone as I was going in the portal I saw something blue I went to it and I saw it was a blue shulker box. I thought it was my friend's box as we both use blue shulker boxes for our treasure like diamond and important items. As I opened the shulker I saw my items from about a month ago when I updated the version from 1.16.200.02. It was like a copy of my old shulker box as I remember I had 30 diamond block before the update and 2 netherite ingots. I think it might be the update otherwise I don't know anything. The first image is when I put my current box and the old box.
Second Image is the old shulker and the third is my current shulker box.