>Basically, I made a circle, and conjured a harmentia demon.
>It immediately jumped the XXXXX we were standing next to, and
>then area attacked, and was able to hit my group and I,
>drawing us into battle, despite the circle. I know angels
>don't work this way.

This is by design...and you are incorrect in that angels don't work that way. They are just more limited in where they can cast their area spells.