Well, I’m honestly not surprised.
Eversong Woods has some NPCs whose damage is a total mess since 2020.
There are some elementals/ghosts, I think they are the Mana Stalker, that kill you in one hit with Moonfire.
I think the total damage is 2000 and at that level you have between 700-800HP depending on the class and spec (with Heirlooms).
There are several threads about that bug.
Normally it’s not a problem because we all kill enemies in one hit up to a certain level. But many times it can happen that they are left with 5-10 health and it is there, in that window of time, where they use Moonfire and kill you.
The problem is that the cemetery is so far away that you lose a good 5 minutes to get there.
Reading about a Chain Lightning doing 20k damage in Ghostlands doesn’t surprise me.