It shouldn't be automatic. Are you accidentally clicking when the battle is starting? That used to be a problem, but I think it got better.
Or is it a target selection problem? You're targeting an enemy, and their animation changes and when you click, your cursor is no longer on their outline? There have been complaints about that. For now, just try and click on the center of their mass instead of an edge. This is one of the quirks that you learn to deal with after a while.
