So I rescued Rugan and Olly from the Knolls and convinced them to let me have the chest with the persuasion check. I then went to the Zhentarim Hideout and I am "welcomed" by Zarys. Thing is, she is standing in a no-go zone. So if I approach her and talk to her, everyone immediately attacks.

I can get around this, but it is hacky. Basically, have to send someone up who has invisibility on and then push her off the ledge down towards the merchant. (This only works because of an invisibility bug where you can push and not break invisibility) There, I have another (unchained) party member waiting who talks to her while she is in the safe zone. This allows me to get paid and report on the chest which updates the quest. But I have to use the invisibility cheat to talk to her.

Obviously the dialogue is there to pay me for rescuing Ruban and to turn in the chest if I want. So it seems to me she needs to be placed in a different spot or you need to redefine your no-go zones.