Ever since the observer had created a stable gateway between the Core and Tannagost, Salaman and his guardians had been frequenting both places. It was not only due to the warriors in the army wishing to see the legendary "revived land", but it was also by invitation of the observer.
The guardian army was tasked to defend Star Cluster X and had not paid attention to the happenings outside of that sector. But now that the biggest threat to the Core had been dealt with, and they were simply waiting for the "Lord of the Throne" to arrive, plus Hao Ren and his droid swarm had taken over most of the defensive works within the sector, it was pretty clear that the mission did not need to go on. Or at least, the entire guardian army did not need to stay put. Thus, many personnel under Salaman's command were freed from duty.
Besides, the other locations within the Plane of Dreams required their strength.