That is exactly what's happening to me too. Really huge let down since you can't avoid going back to the nexus and shouldn't have too. Way to make me regret my purchase Bioware.
I just encountered the bug myself on PS4 and made a thread about it here, I figured I'd continue playing and wait for a patch to hit and ended up doing the Hunting The Archon mission as well. I'm about halfway through and will be able to corroborate if this does indeed fix the issue.
Upon completion of the Hunting The Archon priority quest I was able to load into the Nexus with no issue.
