Stonebrunt Mt. level restriction ?

[Tetsuo]

I was under the impression that the zone did not allow one to loot kills if they couldn't get xp for the kill so the zone wouldn't be farmed by 60's, so I took my level 51 over there figuring I could still get some xp from mobs there.

However when I killed a dark blue, and got xp the corpse still went poof, does the zone also have a restriction for levels 50's or did I just get unlucky ?