This is not bugged at all and is working fine, it is just time consuming. Best way i found is to haunt the area next to the H4, there are 20 mobs on a 5 min timer, it just takes time. It just lacks the eaze the other kill achievement of its type has where you can run into the heroic instance, kill everything, runout, reset instance rinse repeat. While i do agree its a pain to do, Each planet seems to have atleast one of these gems.