Hi. I was bringing a zombie to the nether to cure a villager. He went in first and i went in after. When I got to the nether, the zombie managed to kill me while I was still in the portal. I went back to the portal, and saw that my elytra had made it through to the overworld. I pick it up and go back into the nether. When i got back into the nether all my stuff had disappeard. It’s a singleplayer world. I saw a similar post to this that was “resolved”, but on that post another person commented that he also experienced this in 1.17, so i’m not the only one.