I found this in zone/features.h
Code:
//THESE ARE BROKEN RIGHT NOW:
//enable these to prevent mob hopping when they are pathing
//#define FIX_PATHING_WHEN_MOVING // expensive but accurate
//fix Z on sendto as well, if you still have hopping problems.
//#define FIX_SENDTO_Z
The actual code is in zone/waypoints.cpp in the functions Mob::CalculateNewPosition and Mob::SendTo
Maybe someone with more time and programming skill than me can have a look at this?
Edit: Someone can enlighten us what is broken right now? On first glance I cant find anything in the forums or wiki.