NE40 is a level1-2 router, and NE08 is level1 one. NE08 is required to generate one default route to NE40 automatically. However, the default route cannot be found on NE08 in the topology.
According to ISIS, level1-2 router is to adverise a default route to level1 router. However, level1 router does not generate a default route in the case, which is because that level1-2 router does not receive the level2 routing entries created by others, so level1-2 router will not advertise a default route to level1 router.