My twink wiz spent 3 months quad kiting these buggers from lvl 54 to lvl 59 (camping them mainly for AA points) not once have I seen this belt drop from any of the Tro Jegs.
My guess is that this item is drop by Kraen Flameweaver. The guy that posted this is probably just trying to weave people to a different direction.
Nope. I have spent part of 57th, all of 58th, 59th, and half of 60th killing tro jegs, and believe me I know what drops off what. I almost fell out of my chair when I got an apparently insanely rare drop off a tro jeg *warder*--this is the first time ever I have seen an actual non-spiny-or-research-junk item drop off a non-named tro jeg on the plateau.
I finally got a second one of these to drop, again off a tro jeg flame warder, and went back and checked my logs...have killed a total of 380 tro jeg flame warders and gotten 2 Belts of the Fire Spirit.
Yup it can happen. I wouldn't be surprised if this odd item dropped off a non-named tro jeg. I got a sun soaked tunic off of a regular sun revenant one day. In Scarlet items can drop off of non-named mobs its just very very rare.