Hello,this might not be the right place for this topic but i decided to try since the issue is kinda odd.
I did the achievment Stormpike perfection some time ago the alliance version pvp achievment from AV,yesterday i changed to horde to help a friends with raiding and few quests everything was fine the achievment probably got swaped with its horde version as its suppose to happen then few hours later i go back to alliance side and i lost the achievment and its for 20 points one.I will add screenshots to prove everything,shortly i added it to the bugtracker but my concern is even if the bug get fixed i will not get my achievment back.Dont get me wrong its not the end of the world but its pretty hard to get so my request is pls check the screenshot and contact with me to resolve the issue.
I had the same problem with my character too. Its a fairly common bug for players that faction change several times. And not just AV perfection, it happens with other achievements too like loremaster and reputations. As a fellow achievement hunter, i know that pain. But too bad tho, this isn't a top priority on bugtracker and most people don't care about achievements to upvote it. You just have to get it again.