Post#4 » Wed Jul 22, 2009 8:45 pm
It's an issue that will happen to any mob which isn't in the basement. If a mob on a floor other than the basement runs through a wall, then 9 times out of 10 it will bug out and fall below the world. (or into the basement) After it falls below, it'll try to run back to you but since the floor is there now and it cannot go through the floor then it is stuck underneath. If you were to remove all the mobs that do this then you'd get rid of most of the mobs in the zone. Just try not to run around corners with aggro and you'll be fine.
Jeido, Founder of Evolution