is it normal to leave a line of trim paint on a wall?

Walls and trim are typically not painted that way unless someone requests it (which I've never even heard of before). Just as you stated, there usually isn't wall paint on the trim, and no trim paint should be on the wall (unless they're both the same color of course). If you take a look online at the interiors of different houses, I think you'll find this to be true. I'm not really sure why the painter would do that, especially since it looks kind of awkward. Even if it was supposed to be that way for whatever reason, the painter should have used some sort of painter's tape to ensure that the line was straight and not wavy. This painter definitely doesn't appear to be a professional in any regard. I would probably ask them to repaint the trim area, and I would also ask for a different painter next time if possible.

Hope this helps!

No you are not nuts. Is this guy a professional painter? Sorry you need to talk to him to fix it. Hope you didn't pay him in full. If he doesn't fix it, you should fire him. But talk to him first about this matter.

the guy is crazy

Yes, it is.