Tornado bird boss in a map is borderline impossible to kill

The tornado bird boss in a map summons a huge tornado and this tornado stays in the area for the entire fight and stays on the boss the whole fight. Not sure if this is intended or a bug but I can't see the boss and what the boss is doing, nor can I approach the boss for the entire fight because of the tornado. This boss in the trials of chaos is already a testament to idiocy of people who designed this fight but this mechanic in the maps (which in any other game I would be 100% sure is a bug but in this game anything is possible in the briliant heads of the devs) makes it literally impossible unless you're a ranged build with a huge DPS.

I've had problems with that boss myself.. the tornado will glitch and in an instant be on top of me for an instant kill.. no other boss in the game has killed me more. Its impossible not to die to it when the tornado glitches on top of your character.. Just dropped a quarter of my xp bar gains.. nice