Demon Herder

I'm playing a melee monk with ice strike. I've a lot survival both gear and skills-wise and deleting screen but whenever these Demon herders spawn, they box me in and one shot me, i can't move, i cannot dodge, i cannot attack, i cannot teleport. I just die helplessly without anything responding. I lost a whole day of farming just dying to this same spawn.

I'm thinking Demon Herder is bugged, that dude just clipped me after blink out of sight, away from his cone, way before it even casted the attack... Like the attack came directly on the X axis and I went to the Y axis. Clipped, stunned, swarmed and dead. Lost the breach just because enemies had evasive and dodged 2/10 attacks. I know they don't want the game to be Poe 1, but if anything, any play style other than minions or screen nuke is heavily punished, let alone melee.

I just failed my first citadel, boss dies in less than 2seconds ,but came back to kill the last rare and this demon herder spawned on top of me instant death(full cone attack), map was t15 white! no way this is intended, got almost 4k mana on a CI+MoM+EB build....