Duplication using end portal and falling items

Just had some players that obtained 3 stacks of dragon eggs using this method: https://www.youtube.com/watch?v=JLzXXOwC3ao&feature=youtu.be

Works on 1.9.4 and 1.10, multiplayer.

Tried searching for duplicates, and haven't found any. Maybe they're privately reported?

Anyways, issue seems to be that the cobblestone wall breaks the falling item, while the original item also falls through the portal. Then the item drop also enters the portal.