>>5051814N isn't Mongoloid you idiot, it is Uralic-Finnic
And going by your map it isn't widespread among mongoloids at all, only a few Mongoloids close to historic Uralic and Siberian territories carry it.
Which means they got the gene from Mongoloid women in the area having children with Uralic-Finnic men, those Mongoloid populations didn't have the gene originally