I don't believe there's anything you could call a good reliable location, but the nodes for it can spawn in any of the level 50 Belsavis daily areas. Not just section X. You can also get it from some of the commendation crafting boxes, like the grade 6 crafting box from the pvp vendor.
im open 15 grade 6 crafting box from the pvp vendor. no ED...
where belsavis daily area ?