I saw something posted the other day to do with the movement of the Crown (group leader) effecting this. Not sure where the post went now though.

I have had the same issue. Ever since homestead, there have been so many bugs in general, playing with a team is almost useless. It took me so long to convince my bf to play this game and since the update, he has been put off completely. Only one of us will get experience for the dungeon at a time and it's only the one who is the leader so we have do two or more dungeons to get the daily experience. On top of that, the dungeon finder works less than half the time which is remarkably less than we were experiencing before the update which would have been hard to imagine before. I can't believe I am actually wishing we could go back to how bad the dungeon finder was before. The issues I am having is that the duneon finder usually doesn't teleport us to the dungeon when we are grouped up. When we try to go there manually, it reads that the dungeon has already been done. Also, sometimes the finder doesn't tell us which dungeon we are supposed to be doing so we just all are paired up standing around waiting to see if anyone else in the group knows which dungeon we are going to. In any case, we don't get the experience if we manually teleported anyway even if the dungeon wasn't marked as completed. When will this be fixed?!?! This is happening in xbox, btw.