Something isn't working right with imbue dice and threat reduction. We have ranged characters with 20+ imbue dice routinely pulling aggro from Death's Teeth and Wrath of Vecna (Skeletons in the Closet) on LH/R1/R4. These characters have Cover of Darkness tier 3 for 30% reduction, which is supposed to apply to all damage sources. It doesn't matter what the ranged build is: Alchemist Inquisitive, Arti heavy repeater, throwing dagger, shuriken or bow. They're all pulling aggro off the tank. These are experienced players that have raided for years (and completed R10 raids), so both the DPS and the tanks are optimally geared, built and played.