This mob does not appear to be spawning on a TLP that has unlocked expansions through House of Thule.
Since the Task they are associated with ("Mercenaries for Hire", from Secalna Galnor in the Plane of Knowledge) is marked on this website as having been released with the Veils of Alaris expansion, the gnoll pups are likely set on Daybreak's side to only spawn when VoA has been reached on a TLP.
Secalna will still give you the task, it simply may not be able to be completed until VoA has unlocked and the gnoll pups start to spawn.