Wish I knew, because that's just way bad. Apparently, there's a lot of trade-in bundles for the PS4 that steal positions in the Gamestop charts - but that would imply that people exchanged their PS4 en masse before to get enough stock for those bundles to take away that many sales.
Another reason could be people waiting for the PS4 Fortnite bundle, but that drop is too extreme for just that imo.
I thought the Fornite bundle was a Europe exclusive? Is there a U.S. release date as well?