I have the edition that came as a download when I bought the console. I don't know if that will make any difference, but now when I choose a quest, the marker either takes me to some place unrelated or won't come on at all. For the quest I think called "Transcribing the Mundane", the marker leads me though the cavern with all the glowing mushrooms and then up an elevator and then it disappears. On the Bedlam Job mission, even when I steal well over 500$ worth of things it never says anything about completing the quest. There are a few other small quest like this like "Back to your roots" I think it is, where the marker doesn't even activate. I've made sure all other missions were not selected, and it still just won't work properly. I was able to complete all guild, story, and several other side quests before this issue came about.

I have found that the game may not activate markers correctly if you are in an Interior Cell (for World Map Markers).

Also, try Clearing the Cache on the 360.

By interior cell do you mean activating while inside of somewhere? And I cleared the cache and still the same thing. I've activated two different quest and both markers take me to the same place.

uncheck all other quests except for one on left side of the screen. Don't choose more than one quest.

I've went over the list several times to make sure nothing was active, even the miscellaneous, and it still will either take me to the wrong place or not activate at all.

only have one thing active on the left side. Choose miscellaneous only. Then check the bottom item, the oldest. See if it works.

I have several quests that the mapping does not work or is greyed out. I just google the quest and see where to go to finish it. Just easier than trying to fix broken quests.