Currently there are two achievements which are bugged to my knowing.
One is in Hel Ra Citadel. The achievement goes as follows;
Hel Ra Citadel: The War Horn (5 Points): Sound the War Horn in Veteran Hel Ra Citadel and defeat the ancient warriors who answer.
Last week I've done vHRC a total of 5 times, in which the War Horn was activated each run. In every single one of these runs, no one died on the trash, we didn't wipe and just cleared it before moving on to the final boss. The achievement wasn't rewarded to any group member.
The other that I know of is in Bloodroot Forge and goes as follows;
Hand Wrought Victory (10 points): Defeat the Earthgore Amalgam in Veteran Bloodroot Forge without any member of your group activating the Stonefire Crucible or Flameslake Cauldron. These synergies become eligible to be activated on the pre-final bossfight with the warrior, the mage and the minotaur. We killed it the first time and no one activated, we looted the chest and activated HM which removes these synergies from the boss fight, so we were unable to activate them regardless. We kill the boss and none of us get the achievement, we all checked if we had it before we went in and if we received it after doing the boss fight. To try it again we queued again, got to the same fight again. We handled the pre-final boss fight the same way where none of the synergies were activated. This time we did not activate HM and just burned the boss without activating one of the synergies (we decided to play it safe and not even stand close to the AoEs in which you can activate one of the synergies). Again, we killed the boss and did not receive the achievement.
As a completionist myself it bothers me that I do not have these achievements when I have completely met the requirements. Will these ever see a fix or am I just going to have to suck it up and accept that you're not going to fix content that isn't trending anymore?
In case it helps, my character is called "Salty Sorcerer", which currently has 42 605 achievement points, and I play on the PC EU Megaserver.
PC-EU | CP 2200+ | 52 590 Achievement Points | Salty Sorcerer | Altmer Sorcerer (Magicka) | AD | Former Empress, AW Rank 50 | Flawless Conqueror (602,803 Score | U22), Immortal Redeemer (114,473 Score | U24), Dro-m'Athra Destroyer U25, Gryphon Heart (130,902 Score | U25), Tick-Tock Tormentor (220,587 Score | U25), Godslayer (251,386 Score | U26), Kyne's Wrath (238,405 Score | U27), Unchained (106,377 Score | U27), Spirit Slayer (301,402 Score | U28)