So I was just chillin and I put my shulker box on the ceiling in between the corner of two stripped logs but when I mined it out with a pickaxe (it was enchanted with unbreaking II and efficiency II if that helps) it jut kinda popped out of existence. I checked the roof and under the floor but it looks like it just kinda disappeared completely. It was in an ice spikes biome so I checked under the snow too to no avail. Anyway hopefully you can recreate it and fix it. Have a great day whoever is reading this. Oh also the box wasn’t dyed or anything. And it was my own world so it wasn’t caused by bad connection. Someone else was on the world too and they didn’t pick it up.