XP on other world servers

I recently started visiting Lamia and my home world is Famfrit. I unlocked a mapping exploration achievement that and I saw the XP earned, but it was not added to my total XP. Is this XP lost forever because I cannot earn this achievement again?

Such experience is not affected by what world you are on. We can only guess precisely what did happen. Perhaps you were on a different class.

I seem to remember the exp from these events being added simultaneously with the achievement unlocking. So if you did get the achievement without the exp it might be some form of error. With that said, id say not to worry about it. Most mapping achievements dont have an exp award attached, and the ones that do tend to be less then 1 kills worth of exp. So while you might have lost some small bit of exp, its not a consequential one by any means.