Had the same problem and the cause seems to be that, according to the main loop of the script, the AI goes into "combat"-behaviour if there is another friendly troop in "aware" or "combat" -behaviour close enough (default 100m). Problem was fixed by ensuring that all units on the same side as the AI are forced to "safe"-behaviour at mission start, for example by using the setBehaviour-command (http://community.bistudio.com/wiki/setBehaviour).