Slitherine

Setting up a AI defend order, picking the location (a primary objective) and setting the distance = 1 to give the AI some tactical movement possibility.
In play I find the AI will too often leave the objective making it easy for the human player to move one of his units in place.
So it looks like a static order works best since it glues the defending unit to the victory location.
Or is there a better way to use the defend location order? Setting distance = 0?

If you want an AI unit to never leave its position, definitely use static defense. This is also the fastest (easiest to calculate) AI task.