The Final Assault - Locked outside.

jayteso

I'm on this quest, but I wanted to finish the rest of Coldharbour before completing it, but I didn't grab the wayshrine inside the portal. Now I can't go through the doors leading back to the beginning because they're only usable during a pre-quest that I've already done.

Armitas

Sometimes the game will give you a wayshrine even though you haven't walked over to it. Check the map and see if it's actually unavailable.

jayteso

Someone that was stuck with me found a creative way around the door. To the left of it, there's a crack in the wall that you can jump up with a horse and traversed if you're careful.