Monday night, I ran Tak-Rethan Abyss on a level 8. I was able to kill the Zekvir adds of the first two groups, but not in the third group. In the third group, one of the boosted adds spawned underground. It was untauntable and unreachable. I was able to finish the delve but because that add was unreachable, I was unable to get the bonus loot from killing the Zekvir-boosted add groups. 