Items held from a previous world will still persist visually when creating a new world when tabbed out. The item does not appear in the inventory of the player in the new world and disappears when exiting out of the pause menu.

Steps to reproduce
1. Load a world
2. Hold an item
3. Save and quit out of that world and create a new world, then tab out of Minecraft until it is finished.
4. Observe the item held in player hand, albeit not in the inventory.