Back in approx. 2010 I completed all quests in Eastern Kingdom, Kalimdor, and other places to get achievement The Loremaster. Recently, i noticed that my old low level quests in Kalimdor and other locations appear as if i never did them. I started re-doing some of them in Darkshore even though i finished them long time ago.
I’ve noticed that too. I got one in dread wastes that still shows up on my map when i look for “trivial quests”, even though i’ve already done it.
believe they reset all the quests when transmogs became a thing so you could go back and get the appearances
No, transmog items from already completed quests were retroactive. Meaning you got the appearances that you could use on that character provided you did the quest before hand.