Hello, I traded with user Cruzarex on Gold Server, my Kadabra for his Haunter, for a trade evolution. I forgot my Kadabra was Hoenn though, so it got locked in his PC, as he hadn't yet even beaten Kanto. The notification that my Pokemon would be locked in his PC never appeared. This was at least a week ago, but I do have DM logs. No pictures of the Pokemon in question, however.
I'm unsure if he'll be back on to finish the regions/attest to this. I haven't caught him online recently. The chat showcases I gave his Haunter back, and it evolved fine.