I died from fall damage and I was unable to pick up some of my items.  Most of my items were able to be picked up but some weren't able to be picked up after walking over them several times.  These items eventually despawned.  Items not able to be picked up included diamond pickaxe, diamond chestplate, and rails.  My inventory wasn't full at the time and I was also wearing elytra when this happened.  I tried to recreate the issue but have not been able to.