It is not possible to continue on quests for the achievement of, Vol'dun

[kinlones]

First of all, my apologies, I am using google to translate as best as possible from Spanish to English

It is not possible to progress in the achievement of, Secrets of the arena

Achievement

damaged mission

when curing the NPC (Serrik), it disappears and it is not possible to continue

Img google
Img 1
Img 2
Img 3

[VúSale]

Just wait for the problem to be fixed.
This is apparently a bug.