Citadel bosses one-shotting when they really shouldn't be?

I noticed this last season, and it's still happening this season, but citadel bosses (which I'm pretty sure have no one-shot mechanics) are one-shotting insanely tanky min-maxed characters, and there's no indication of what ability killed them.

This season I'm running a bear with 13k armor, 2400+ life, a little (200) ES, and 2k+ mana, with mind over matter, and about 140% armor applies to elemental damage. I ran a very tame T15 map on Iron Citadel, got to the boss, leapt onto him and immediately as I was about to land I went from full health, ES, and mana to dead instantly.

Last season I was running a chaos inoculation invoker with some 12k ES with meditate up, and I would regularly get one-shot by citadel bosses.

In both instances, I can face tank max Xesht's hand drop and multiple fist slams, but these random bosses somehow one-shot me regularly.

I also noticed the Geonor citadel boss "ice beams from the sky" attack is doing crazy high damage. Died on my first 2 attempts getting 1 or 2-shot with no damage mods on map (3.2k life, 1.3k ES, capped res and Avatar of Evolution). Always froze me in 1 hit as well despite never having issues with freeze otherwise.

A bit overtuned for an attack that difficult to reliably dodge.

I'm really getting sick of these 100-0's in normal maps. Just had it happen again in another one. If I was playing HC I'd be absolutely pissed. There's no reason these bosses should be doing this amount of damage. This was an INCREDIBLY tame T15 map and I got one-shot with 15k armor, 23k of which applies to elemental. That means this normal map boss (hint: it wasn't even a powerful map boss) was doing over 10k damage in one hit with the reduced armor effectiveness at 10k.

A bit excessive you think? Nobody likes playing games with insta-kill mechanics GGG.

And now another mediocre T15 citadel boss. This is ridiculous.

Reworked the character, I'm now sitting on 30k armor with 5000 combined hit points before armor (life, ES, and mana with mind over matter). Another random map, Hyena boss one-shots me.

Screw this game.

Are you face tanking them?
You're supposed to avoid hits no take them like it's nothing...because i dont think 30k armour is enough against big hits they way it works, they can crit too so dont face tank