Harbinger in Delve + Nemesis mods.

How exactly are we supposed to win this. I'm being blocked off by a Harbinger node at monster level 81 / depth 126. Harbinger was balanced to be challenging as a league mechanic as is, Now monsters are further enhanced with Nemisis mods. Was this unintended buff to Harbinger mechanics discussed at all by Grinding Gear staff? Is this a fight that is even possible to win without extreme RNG favoring you or being massively over leveled? I just don't get it. In general I've been enjoying the league so far, but I just can't see a way of wining this specific set of encounters.

Delve prevents kiting into the darkness, the length of Harbinger encounters make touches non viable. Using TNT/Explosives isn't viable due to the number of waves the Harbinger spawns. Staying within the clearing of light around the location is nearly impossible with nemesis spawns and Harbinger totems. If you're lucky enough for there to be a corner to hide around that is in the circle of light eventually one of the monster packs spawned per wave will have a nemesis mod that will one shot you when used in conjunction if you're not actively kiting, which again isn't possible because delve makes monsters away from light immune. And there is no reaction time to them appearing right next to you in a mass of other monsters until you see the skill effect, which is normally to late.

Level 88 Chieftain, Main links are Righteous Fire and Chain Throw with Flame Dash for mobility and molten shell. As I said before, I've enjoyed most of the challenge of this league but even for me this seems like a completely imbalanced encounter.

Delve with archnemesis mobs is bad now, sadly, harbingers are not even the worse..
Deeper, the ground becomes almost completely filled with various overlapping ground degens..

GGG already posted, that They do not do anything with old league contents (like this) before 3.19..