honeyhoney
commented
6 years ago As you've already guessed this is an issue with the maps on Hellfire 2 rather than the mobs themselves. Since the main server's hardware blew up Hellfire 2 has been on backup hardware with objectively worse maps.
Can't really see a good way to resolve this without generating better maps.
Although there may be some value in trying to change their movement type so they could potentially fly or something as an interim "fix" just to make progress on this boss reasonable.
With the los not being that great on HF2 atm Gorefiend's Shadowy Constructs are going under the floor when they hit the stairs while on their way to Teron. They are not targetable while they are under the floor says the raiders.