so basically, in some cases, if you die and the items fly a bit, mainly from falling from a height or a creeper explosion, the items will look to be in one spot, but when you go to pick it up, its not actually there. the item fell in another spot, and the hitbox is there, but the texture of the item that can be seen is in a completely different spot. you arent able to tell where it actually is, and you have to run around the area to hopefully find it. i was going back to my house in one instance on my xbox, and fell in a ravine, and the bug happened when i died, and i was unable to find my netherite pickaxe. i also confirmed it to be on pocket edition after being blown up by a creeper and having it happen again.