Do you pick up the trail of the cycle and then just lose it after one of the kills? Or do you just go on and on forever and never get the, forager is it? Are you sure you're following the right cycle? If I remember there's more than one cycle and they are separate from each other. I haven't done this in a long time, but it should be as easy as killing the right mob and on track, the new mob pops instantly and you go and kill him, each time generating a new insta pop. If nothing shows up new, it's out of your track range, run around a little till you see him. I can't remember if I did this with 100 track or 150, so if you want an edge, and don't have 150 yet, try upping that to increase your tracking range.