Maybe im missing missing. But im pretty sure that, a while ago, cloudkill was changed so that the instant-death effect was no longer a effect that the spell gives. I was so used to cloudkill not having that, then all of a sudden, when I run Haunted Library with a full party, I failed a save on cloudkill and I died instantly. On a side note, the whole party wiped as well.
Is this a bug? Is the insta-kill effect still on cloudkill? And if so, how exactly does it work?