Aviak falls under world in Lake Rathetear

[bwe]

I was attacking one of the aviaks near the Arena (not the aviak guards) when suddenly it "jumped" and fell under the world. It could still attack me but it was too far away for me to melee, and I couldn't see my target to cast on it.

[bwe]

More info:

It's the Aviak furthest on the right when you are facing out of the Arena cave. If you cast on the mob and then run back into the cave out of its line of sight, the mob disappears but is still able to hit you. If you stay in the cave, the bird will never appear, but if you run out of the cave it drops repeatedly from the sky then acts like a normal mob.