Sorry, just saw that mispell, but fixed with links, this one is good to check as well
at this mobs room in lake of ill omen (
http://wiki.project1999.com/Chancellor_of_Di%60Zok ) theres like a bump, mini stair, higher elevation, that slightly change of Z elevation bugs them easily, you can jump, mobs cant and if you jump and pull them up, they will bounce up and down, sometimes they do come up, but about 80% of the time i had them bugged.