I had not unlocked empowered monoliths yet (nor completed any unempowered monolith) nor defeated any harbinger, and I was tagging along with my husband with him selecting nodes. We completed The Last Ruin (unempowered). Then we progressed to and were fighting the boss of The Age of Winter (unempowered) which was the last monolith he needed to unlock empowered monoliths. I died during the fight, but he finished it and a harbinger showed up and he killed that.
After that we were able to go to The Shattered Road. He said there was an NPC present with quest, but for me the NPC was invisible with only a chat bubble floating around that I couldnāt interact with.
Iām guessing this will unlock for me when I have completed Spirits of Fire and therefore unlocked empowered monoliths, but I suppose the fix would be to make the NPC interactable and say something like āyou donāt have the right oh you donāt have the rightā or whatever to people that are just there tagging along.