Apparently last weekend Xbox One and PC Destiny 2 players found a way to get a weapon that was only allowed on the Playstation 4. The Wavesplitter was originally a Playstation exclusive. That scoundrel Xur had been selling the weapon this past weekend. Those lucky players that bought the weapon will be able to keep it, with a catch. Bungie responded to the glitch with a statement that included this part.
After the fix goes live, they will still have it in their inventories, but will not be able to equip it until this weapon enters the general Exotic loot pool in September 2019.