actually, by blizzards own standards, i’m amazed that there isn’t an apostrophe in both versions… regardless of which is correct.
if you read quest texts, this is a very common mistake… but after having a bit of a back and forth with various reps, there was apparently some reasoning behind why this happens, and how nearly all possessives are managed like this.
(it was years ago… i can’t recall the “why”, but it wasn’t really a good reason) 
still bugs… which should be reported here:
eeep.
stay safe