The new Pokémon Brilliant Diamond & Shining Pearl patch has added 'PokeDupeChecker', which checks for clones in the save data (party, box, daycare). Anything detected as a clone will be flagged in the PKM's data structure, and will be prevented from being traded. pic.twitter.com/vWdj4E1JtS

— Kurt (@Kaphotics) February 22, 2022