Oriath Square

Cannot get back to this area after you do the quest as it turns into Ruined Square

2 Challenges need this area: The Matriarch and Guraq, Daylights blade vaal area

I think a fix for this could be to allow to go back to this area the same way you can do a new instance... but instead it will list both areas to open a new instance and you pick one

bump

Guraq, Daylight's blade' area is "interchangeable".
You can find him at Ruined Square's vaal area.
As well as the other guy, can be found at Oriath Square vaal area.

As for the Matriarch - you can just ask at global chat for someone to open a town portal to the Oriath Square. Game would allow you to go there this way.