incomplete quest chains

I was leveling in Hillsbrad today on my 28 horde warrior and noticed a few quests that were not showing up or were disappearing after attempting to accept them. WANTED: Baron Vardus is a quest that should be acceptable at lvl 18 but doesn't show up on the wanted board after completing the pre-requisite quest WANTED: Syndicate Personnel. Also I noticed the final quest to Battle of Hillsbrad for the Undercity turn in disappears upon acceptance and reappears at the npc as a higher level quest I am not sure this happened in this particular patch but in later patches the quest is also acceptable at levels as low as 18. Just curious was this intentional to attempt to nerf twinking at the particular bracket?