This is funny, to think most newbies would likely to ignore the notice regarding the unfinished chapter/realm. I also fell into this sort of trap back when I was a newbie and I was focusing on ranking to 30 with main quests. I am certain the reason why this happens is because after a main quest is accomplished, there will be a dialog to confirm whether the player continues or not. Whilst getting fed up with the constant dialog after main quest battles, the player usually ignores the content of the dialog.