Fortnite has such a large pool of all kinds of items and weapons that even Epic will get confused sometimes.
During Tuesday’s update, Epic accidentally triggered the wrong weapon as it should. For a while, players were able to find the old green pump. This was not intended, and so the occurrence of this weapon was extremely rare.
It was only possible to get it thanks to vending machines, Epic realized after some time, and as a result, a small bugfix was introduced to fix a bug with the pump. This one has disappeared from the game again.
Withdrawn for good
Many people suspected that this is not a bug at all, and Epic will slowly restore old weapons, items, mechanics. The weapon was associated with, for example, airplanes and their return. It just turned out to be a mistake.
The whole thing was so short that some people did not know about it at all and for the first time, people heard about the whole thing only when the pump was withdrawn from the game.