Ha, I also have two creepy weirdos.
The first buys my crafted items and immediately resells them to undercut me on the market board with items I have crafted. He's been doing this for at least 3 months.
The other is mysteriously always in the same area as me. I do a lot of treasure maps and at first I didn't notice it until I looked up. He sits on his mount, flying, high enough above me and watches me.
I guess that the sun and the heat of the summer doesn't suit everyone.