No guys. You can enter the dungeon, it’s not bugged.
What’s bugged is the reaction of the server when you try to enter a dungeon when it’s full.
Yes, dungeon can be full, there’s a limit to how many parties can enter a dungeon at one time. Well, that’s at least what I believe.
in iCBT2, what happened was that when it was full, you simply wouldn’t be able to enter with your party.
However now in EA, something is simply wrong, and when you try to enter when there’s no more slots for the dungeon, the server kicks your out, instead of just not letting you go in, like it was in iCBT2.
Anyway, you can still get in. Get your party together, and have everyone keep trying to enter (crashing, going back in and keep on trying). Once one of the parties that are inside are finished and get out, you will be able to enter. If any of your party members get in, you all will be able to get in, since you party will have the slot for the dungeon.
I’ve done it this way in iCBT (no crashing, though), I’ve done it yesterday this way, I’ve done it today. It works 100%.
Just explain to your party what’s the deal (so they don’t leave and actually keep trying) and you’ll be able to do it.
Alternatively, you can wait in front and when you see people suddenly appear (party that was doing the dungeon), you can press enter then to enter (unless someone beats you to it). I think the first method is much safer, just have your whole party help. 
It can take a bit of time, but it’s worth it, especially if you’re just level 50. 2 runs are 8-10 levels from 50.
