Unkillable Mitrix

[Iracondus]

As the title says, second he started last phase he turned unkillable, his health instantly regening back up to full if I don't attack him. Second he loses health he loses a chunk, maybe about 1/10, but never goes lower than that.
I suspect it has to do with the new "Warped Echo" item, which causes a portion of the damage you take to happen over time.

[lucille_lieu]

we had this same issue yeah

[Char Momone]

Same issue here as well, i was playing engy alongside a seeker and i could only damage him with missiles, the turrets wouldnt shoot, my bombs would bounce off, and my spider mines couldnt even move. also had a ridiculous effect spam with aurelionite that tanked my framerate at didnt do any damage either

[Empyreal]

i have the same issue, he doesn't take any damage.

[Commando Keen]

I can second this. I did get a recording of the last 10 minutes if necessary.

[ugnor the incomprehensible]

same here, got a video of it too

https://youtu.be/HAqOxbVbd5o

[mr-peanut403]

I'm having the same issue. Interestingly, I could kill his solus core probes.
Character:
Engineer (main, Spider mines, harpoons, stationary turrets)
Difficulty: Rainstorm
DLC: Seekers of Storm, Survivors of the Void

From memory here's the items I had:
----New Items----
Nox. Thorns
Chance doll
Chronic Expansion
Luminous Shot
Warped Echo

----Old Items----
Gasoline
War horn
Ghor's tome
ATG
Bandolier
Fuel Cell
Hopoo feather
Ignition tank runalds band
war horn
will o wism
Ben's Raincoat
Spare drone parts
Irradiant pearl
Empathy cores
tri-tips
Sticky bomb
PGH
Opal
Monster tooth
Bungus
Fireworks
Cautious slug
Spare Drone parts
Lost seer's lenses
encrusted key
pluripotent larva

Other notes:
It seems I 'switched teams'. 2 void crabs which were trying to get me before now did not target me, and I could not damage them. I *could* target Mithrix with my harpoons and mines, but no damage would be dealt upon impact. Mithrix *gained* health when hit with an attack from the void crabs. the void crabs never tried to hit mithrix on purpose, but would sometimes hit him by chance.

[mr-peanut403]

Another report here: https://steamcommunity.com/app/632360/discussions/1/4764332864593844253/
https://steamcommunity.com/app/632360/discussions/1/4764332864593776203/
https://steamcommunity.com/app/632360/discussions/1/4764332864593286286/

[BlueDonut]

I had the same problem but a little bit different.

I was playing railgunner E2 and tried to kill Mithrix at his last phase when he takes all my items. Neither me or my drones could damage him. There were no damage numbers at all which is interesting. My XQR Smart Round System (M1) just orbited around Mithrix and other abilities dealt ZERO damage.