FYI, I have it unlocked via Venari rep gains, and I’m nowhere near the giants/elites that have true sight. No dots on me, no debuffs, nothing. Popping an invi potion in Perdition Hold instantly removes it, but classes that can stealth/invi aren’t exempt from using those spells in Perdition Hold, and they actually work.
The potion in question is Potion of the Hidden Spirit