Venore swamp Stairs

[Wowplayer]

cavebot will not go up these stairs in venore, i'll attach the ss which i took. this is the most easteren venore rotworms spawn. it does go down the stairs correctly, but if you try to go up the stairs it gets confused. I dont know if im doing something wrong... but i think not, i add the waypoint below the stairs and then next waypoint when i'm up the stairs.

http://imageshack.us/photo/my-images/194/venorestairs.jpg/