Have you tried to lower any settings? We have not done any optimization passes atm so there is a lot going on with how monster girls look at the player that can cause problems.
alright also as a quick side note its my gpu taht cant keep up so normally that only caculates graphics not the processing of sight for npc's (if i am correct been a while since i have done game coding). sometimes its a problem with the poligon count of your models. from what i can remember these sort of problems can be solved by making it so distant models get loaded with less poligons since distant models wont need as much details anyway. but hell to really know more i might need the game code.(and well i might also be wrong in all this been 3 years since i have studyed some game development)