Stuff dissapearing amediatly after death

When me and my friend were messing about on my survival world I put all my armour in a chest before I he killed me (for a reason unknown to me and Im pretty annoyed to be honest) But anyway when I loaded back in all of my things had despawned amediatly elytra, full netherite, rich things ect. So I just want to report this bug so other people dont have to go through the trauma of loosing all their things.

 

The world was on 1.17.11