Just in case ZOS isn't aware of it yet, in the Arena district not once could we get all 4 of our group members inside the arena itself. The gate blocking the way let in 3 players and the fourth has no option to hit 'e' and open it. We tried the standard things that you try when, for example, fishing is unresponsive or there's a delay in the chest opening, etc. but nothing worked. A whole set of 12+ enemy players entered the arena with the 3 group mates, right in front of us, but the fourth player could never access it.
It wasn't just one of us, after we left and entered again, and the player who couldn't get in abandoned quest and got it again in order to gain access, a new member who was previously in now couldn't get the gate to respond.
I think it might have something to do with not being able to access doors while engaged in combat, but the 'engaged in combat' status is pretty loosely defined in IC where you're very rarely not engaged in combat.
On a side note, I think you know about the massive crashing on Molag Kena, right ZOS?