Question with new warband achievements?

So, ive always been one to sit and switch between chars. it used to bother me doing that though since stuff like lore master the big lore master achieves were shared, but not like the individual zone clear (which always bothered me on my lesser used max characters).

I kind of have ocd and having 1 character with a legit empty continent or 2 and then others that don’t kind of bothered me but threw me off of alts since i aint got time to clear lore master 13 different times. but yesterday i noticed something my officially decided main hadn’t done some of the zones in kalimdor yet so i did the northern barrens and the quest were there, but i got the notifications of chapter complete but upon clearing it no regretting the achieve.

So my main question with the backstory is if it says earned by warband its technically done already and the only reason to clear a zone i already have done is to clear quest markers? and i noticed some achievements say earned and thats it and other say earned but like some variation of not by current toon or still can or something like that.