Once outside these dimensions you get a 'no cuboids found' error
Doing a ps visualize gets a 'no fields found'

odd... seems to be ok now?
No, it only happens north and east
Doing a visualize doesnt seem to work, it says it is happening but you cant see anything
However, doing an expand/contract triggers a visualization that does work
Mobs seem to be spawning in the expanded area also, not sure if that is specific to just north and east as its all lite pretty well