Usually, when a player connects to a multiplayer server, they are given a brief period of immunity to most types of damage.

However, in the latest snapshot, if this effect prevents otherwise fatal damage the player will still survive but their items will be dropped on the ground and their death message broadcasted. However, they will keep all items in their inventory, meaning there is a cloned version of the item on the ground. Both versions of the item(s) are fully functional.

This bug only seems to occur for some damage types, notably witches.