Bug? Mob spawns beyond unopenable gate

Right so, the gate in the cemetery of the forsaken isn't supposed to be openable. But I've never seen a mob there before. But lo and behold today there actually was one while playing on my level 8 Witch Doctor on the Shattered Crown quest.
http://imgur.com/a/ViKIH

Now, I tried attacking him but the gate protected him. So I ran around and found a sweet spot. From there I could toss haunts at him and his minions and just kill him. So I killed him. He didn't take more haunts than usual to die, so I suppose he wasn't of a higher level than the mobs around. I could not reach his loot.

I wonder what's so special beyond that gate if the mobs there aren't so tough. Unless he was meant to spawn in the cemetery but just got stuck, lol.


edit: Oh, and in general Pages of Training were dropping like candy for me on this run. Usually they don't drop until the kill the Skeleton King quest, but they were all over the Defiled Crypts today.