My linkshell was trying to do Einherjar today as our normal time, and the person breaking the lamp tried to enter and couldn't because "somebody" was already fighting mobs (he broke the lamp, and had not entered yet, so I don't know how anyone could be fighting mobs inside).
He already broke the lamp and everyone had theirs, but he couldn't get in, which resulted in ourselves not able to enter. We called a GM, a SGM, and still nothing could get done.
What we did find out is, however, that somebody in his party (was in his party, but it could be anyone who has a lamp for all I know) had just finished his Odin quest up to the first CS needed in Hazhalm Testing Ground's Door (the one that you trade the lamp to enter) and was watching the CS when the glass was broken, so that is possibly the reason why we couldn't get in at that time.
After we lose the lamp, and had to go get a new one, we all entered just fine, so I do believe that CS was the reason.
Just a heads up for everyone, because this might be a problem for you guys now.