Note that his edits in Poland appears ok, but that I have personally reverted a fake island he created off the coast of Denmark (see https://www.openstreetmap.org/changeset/50439199) as well as reported him to the DWG (see the block on his profile).
Ah, because (if I remember right), someone else (Edit: you) pointed it out, probably via a changeset comment, and I stepped back to let them sort it out.
Googling brings up nothing, so like I say, 99.9999% sure…