Zar Wali the Bone Tyrant and Mana Siphoner

When Zar Wali the Bone Tyrant spawns with the mana siphoner mod, it seems to overlap the area with itself and does an immensely amplified effect, draining mana and life exceptionally fast (probably double or 3x the rate) such that a mana flask isn't even enough to let a melee in range of the boss. This needs to be tuned since it's extremely difficult for melee to engage with this boss due to limitations on hitbox.

Same problem
Encounter this dude with with the mana siphoner twice.
Totally unfightable

Same here.
Only fought him once like that, probably died on that one.
This guy should probably not be allowed the mana siphoner mod.

Pretty much impossible to beat with melee unless you can one tap him.