From patch notes:
Please note during this week, access to the Necrom Chapter will be restricted to those who pre-purchased the Chapter to test proper access levels ahead of it launching on June 5.
Before this, I created an arcanist, checked the skills and took her to Necrom to find out about the new world event. Haven't found out yet other than picking up a quest.
After this, she is still there, in Necrom. I have not pre-purchased.
Just took another character to Necrom. No problem. Guess access is not working as expected yet.
Favourite NPC: Wine-For-All
Mostly PC-EU , with a lonely little guy on NA.