The current owner does not have a kanto dex cert, nor a johto one,
so um is this a bug? The current owner doesn’t seem to know why he
recieved it from a trade either
There was a bug few weeks ago, where if you had the dex
entry of any type of Mewtwo (Event Shadow Mewtwo or Shadow Type
Mewtwo), you were able to trade the normal Mewtwo, even though it
should be only tradeable once you have its egg dex entry. The bug
is fixed now (means you can only trade normal mewtwo now if you
have its egg dex entry), and we should forget about the ones which
were traded in that period.