Titan Grotto boss Zelma Wrath broken, not taking damage. cant progress

see title

went in with a coop session. we started to do damage, no problem. then, no damage at all. Boss also seems to not do damage to us on occasion. attempted 3 times.

attempted solo, same result.

previous boss in mastodan badlands was successful in coop. no bugs.

hope this helps,

a Towel

This happened to me as well on hardcore, after he moved for the first time he became invulnerable. After letting the instance reset it worked fine for me tho.

Sorry to not have any more info.

Hey, how you managed to reset the instance? I am stucked in the boss fight with the titan

Same happened here with a coop session. After the boss first movement it was no longer targetable, so it was not taking any damage. We tried to die and start again, but it didn't helped. The only way to fix it was to go through the instance alone.