We have made a change to the way that NPCs decide whether they retreat or retaliate to help prevent some unwanted behaviour where NPCs neither retaliate nor retreat. In particular, this affects how monsters such as Callisto and Vet'ion will behave when lured to the limits of their wander range. This change applies to all monsters with long range attacks throughout Old School.
Taken from the Key/Seaweed update post. Just thought we should be aware before we do any raids in surrounding areas.