[digush]

i've noticed when a mob is fleeing (Below 20% HP) for some time it will disappear out of sight(no where to be found) but it is still in casting range because i can cast, but low and behold "You can't see your target from here"

So the mob is clipping/ i.e. wall_hax/hiding underground.. eventually it will come back to it's spawn point though after a while