Thats not a bug. Its simply that you have no quests within your level range or profile to do. You simple need to open your profile, and add another area for picking up quests your level for your current level until the next range. You also need to add hotspots that go somewhat near where the quest objectives take place. I'd suggest using <RandomizeHotspots>True</RandomizeHotspots> so that you don't look like a bot running in the same straight line everytime you go to the next quest part. You will get grind xp along the way. Also make sure you add the factions for any mobs you want to kill for quests or it will only be able to body pull aggro mobs. I've got my private 1-60 Questing profile almost done. I'm up to level 56 on a tauren. Each beginning will need a profile for their quests, until they hit some main stream part of game like the crossroads for horde. But these take less than a hour to make with pretty high results from them if you know what your doing.
Well wired, I already edited my quests settings one hundred of times, made fresh instals, restarted wow, bot, computer and im still not able to do some quests in Dustwallow Marsh. I added hotspots all over dustwallow marsh, switched to grinding mode to see if i missed any mesh but still didn't solve, I just ignored questing there and went to another place.
I'm ally, and tbh it was the best place I quested before that happening, I did shitloads of quests there.